8057747 Happy Maths 3 English

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~~::.~HAPPY MATNs-


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Happy Maths - 3 Measurements by Mala KumarPratham Books, 2008

First Edition 2008

Read- i i n d i a1 ? . . . . . . . . , , ; "'tQr~

Illustrations: Angie & Upesh

- - - - - - - - - - - ~: This series is sponsored by

Pals for LifeISBN 978-81-8263-908-9

Registered Office:PRATHAMBOOKSNo.633/634, 4th "C" Main,6th 'B' Cross, OMBR Layout, Banaswadi,Bangalore- 560043.({) 080 - 25429726 / 27 / 28

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Published by:Pratham Bookswww.prathambooks.org~s~........ome rights reserved. This book is CC-BY-3.0 licensed.ce \IJ Full terms of use and attribution available at:

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Written byMala Kumar

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Happy Maths - 3Measurements

Illustrated byAngie & Upesh


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Sankhya and Ganith have been learning a lot of thingsin their mathematics class.

Join Sankhya and Ganith in theirhappy discoveries about mathematics.

Zzero and Eka are friends of Sankhya and Ganith.

In this book, Sankhya and Ganith have fun measuring alot of things.

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Sankhya and heryounger brotherGanith enjoy eachother's company.They go to school

together andthey play together.

Sometimes they fightwith each other.One day they

climbed to the top ofMeghdoot Hill.They shouted as

loudlyas they could."I can shout louder

than you!"shouted Sankhya.

"No, I can shout louder than you," screeched Ganith.Sankhya and Ganith have learnt to measure many things.

They were surprised to learn that we can measurealmost anything.We can even measure how loudlywe shout!

Measurement and managing information are part ofmathematics.

Usingmathematics in our lifecan be very entertainingand useful.

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" 10fingers," saysGanith, whose fingers are a little chubbier thanSankhya's.Ganith picks up a ruler, and measures the top of the book." 12cm," he says.

I. If the width of the book is 12cm, on an averagewhat isthewidth of each of Sankhya'sfingers?

2. What is the averagewidth of Ganith's fingers?3. Use the ruler to find your height and that of your friends.4. Can you think of ways to find the width of your classroomwithout using your ruler or any other measuring devicerepeatedly? (You may use it ONCE!)

My Classroom

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Under a Banyan Tree

Sankhya and Ganith were on a school picnic to the Big BanyanTree, which is near Pune in Maharashtra. The teachers hadwarned the students not to run off on their own."There are more than 320 pillars of the aerial roots here, and itis easy to get lost," warned Saroja madam.Sankhya tried counting the number of people around her. Shecounted up to hundred and then gave up."Some 20,000 people can stand under this tree's canopy," saidVenkat sir."This banyantree is supposed to be the biggest one in the world.It hasa perimeter of 800 m," added Saroja madam."What is perimeter?" asked a little boy."Perimeter is the measure of the length of the boundary of atwo-dimensional figure. Children, sit down here and I will tellyou a story about perimeter."


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A Circular PlotStory by R.K.Murthi

Maharaja Vijaya Vikram wasthe ruler of a state in India.He was fair and just, kind andgenerous.One day, a poor villagerarrived at the court of theruler. He was stopped atthe entrance of the palaceby the guard. He told theguard that he would like anaudience with the Maharaja.The villager was thin andfamished. He wore clothes

that were clean, but had several tears mended deftly. It was clearthat the man was indeed very poor. The guard glared at him withcontempt."Vermin of the land," he spat out, in a loud voice. "Get back towhere you belong. The Maharaja is busy discussingaffairs of thestate with his advisers. He has no time for people like you," theguard, a new recruit, tried to turn him away."But I am his subject. And it is his duty to look after his subjectsand to attend to their needs and welfare," the villager pleaded.'~re you trying to tell me how the Maharaja should conduct theaffairs of the state?" the guard rolled his eyes angrily, while tellingthe man to scoot.

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"I will wait," said thevillager."You can wait till thecows come home,"the guard laughed incontempt.But his laughter diedin his throat when hefound MaharajaVijayaVikram walking downthe broad footpaththat led to the mainentrance. With himwas his chief adviser,PanditVidyasagar.He

perked up, gently shoved the villager to one side and stood atattention. When the Maharaja reached the gate, he saluted theMaharaja and said, "Maharaja Vijay Vikram ji ki jai ho."The villager repeated the call. His voice was sharp and tangy.The Maharaja heard the man and turned to him. The villagerbowed.The Maharaja smiled at the villager. "What brings you here,my friend?" he asked."0 Noble Maharaja, I am a poor man. I own no land. I work onland that belongs to others. I work all day long. But I get verylow wages. Often I find no work. Then I starve. So do my wifeand children. Give me a piece of land. One on which I can workand raise enough food to keep my family above want," the manspoke clearly.

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The Maharaja's eyes quickly ran over him. He was so thin that hereminded the Maharaja of a walking skeleton. Yet his voice wasclear. And he presented his appeal clearly. He did not stutter orstammer, as most people did when they came face to face withthe Maharaja. That impressed the Maharaja."You speak well, man," the Maharaja looked pleased."Your Highness! When I was a boy, I studied under PanditVijayeswara. He taught me how to read, write and count.

He introduced me to squares and circles. He taught me howto calculate perimeter and area and the volume of figures. Itwas difficult, but my beloved teacher was patient. He explainedevery detail, againand again. I wanted to learn more, but he diedsuddenly. If only he had lived longer! Then I would have learnedenough to be ateacher. Now I live in poverty. If only I own a pieceof land! I shall till the land, make enough to rise above poverty,"the villager paused.

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"You studied under Pandit Vijayeswara? He was the wisest manof our state! How we miss him, even today," the Maharaja sighed.Then he turned Pandit Vidyasagar and said, "Give him what hewants.""Yes, Maharaja," Pandit Vidyasagar replied."Where will you give him land?""To the east of the capital lies a vast tract of arid land. Nothinggrows there. We have prepared a plan to reclaim the landfor cultivation.We have laida canal. It cutsthrough this tract.Here we havesettled somefarmers. We cangive this mansome land there,"the ministerreplied."How much land do you need ?" the King asked.''A piece of land with a perimeter of ten thousand feet," thefarmer replied readily."Perimeter! What is so great about perimeter? We have neverheard such a request in all these years. People usually ask for anacre or two of land. They bother about the area of the land, notthe perimeter," the adviser raised his voice ever so slightly."Oh ReveredSire!Can beggarsbe choosers?Iwill acceptwhateveryou allot. But you askedmewhat Iwant. So I expressed my wish,"the farmer spoke politely, yet clearly.

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The ruler bent forward, looked into the eyes of the farmer andasked, "I think you have something in your mind. What is it?""Your Highness! Lead me to the central courtyard. Get me astring as long as my forearm and also a chessboard. I shall thenshow you why perimeter is important," the farmer bowed."Come with me," the Maharaja walked back to the courtyard.A guard ran to fetch a couple of chairs. He set them down. TheMaharaja sat down. So did Pandit Vidyasagar.The villager sat onhis haunches, on the stone-paved courtyard.The Maharaja told the guard to fetch a chessboard and also astring as long as a man's forearm. The guard moved out quietlyand returned with the chessboard and the string."Let us have the grand show, my man," the Maharaja waved hishand. The farmer sat cross-legged on the floor. Heset the chessboard beforehim. He used the string toshape, on the chessboard,a triangle. Then he turnedto the Maharaja and said,"If it pleasesYour Highness,please ask someone tocount the full squares thatlie within the triangle. He must treat every square, most of whosearea lies within the figure, as a full block. He must omit everysquare, most of whose area lies outside the figure," the farmerlaid down the terms."Would you like to do that, Pandit ji?" the Maharaja turned toPandit Vidyasagar.

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"Gladly, Maharaja," The Pandit got up from his seat, walkedacross, bent down and took count of the squares enclosed bythe string shaped like a triangle and noted the figure on a pad."That is the area of the triangle, Your Highness," the farmerpointed out. "I know," said the Maharaja.The farmer now formed a square figure with the string. PanditVidyasagar counted the squares held within the shape andrecorded the figure. The farmer formed in turn, a rectangle,a hexagon, a heptagon and a circle. The courtier recorded thenumber of squares held within by each shape.The farmer took the chart from the hands of the courtier andheld it in front of the king. "Your Highness! The length of thestring is fixed in all the cases. So all the figures I made had thesame perimeter," he said."That is true," the Maharaja agreed."Yet the area differed according to shape. Check this list,Maharaja.You will notice that the circle formed by the string heldthe maximum number of squares and hence the maximum area,"the farmer explained.


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The Slow Horse RaceA king wanted to test the intelligence of his two sons."Take your horses and ride out to the end of my kingdom. Theprince whose horse comes in last will be declared the winner,"proclaimed the King. "You have to come back to the palace bysunset."We fight over being the fastest, the highest, the farthest or thelongest. Here was a problem that required the contestants to bethe slowest."If I try to ride slowly, you will try to ride even more slowly,"pointed out the elder prince."If we ride very slowly, we will never be able to reach the endof the kingdom and return to the palace before sunset," said theyounger prince.A wise old minister saw their dilemma. "Young men, why don'tyou just ..." he whispered. "That way, the race will get over verysoon and there will be a clear winner."Read the story very carefully. Then you may be able to guesswhat the wise old man suggested to the royal young men!

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Fastest, Highest, FarthestWe need measurement to compare our respective positions.We are usually not worried about being the slowest.

The Cheetah is the fastest mammal ~----: ~gon earth. It sprints at I 10 kilometres ,. ~an hour. ___.~ ~ - - - - ~ ~

A flea (which usesa dog's body as its playground)is a long-jump champion. It jumps a distance of 33centimetres. With a body that measures just 1.5millimetres, this jump is 220 times its body size.

An ant can carry 50 times its own weight.

The Swift is the fastest champion in the sky. It candive at the rate of 200 kilometres an hour.

Bees use 20 grams of wax to build a honeycomb Mthat can store I kilogram of honey. ~The honeycomb structure of thehive made up of hexagonal cells makes it thestrongest arrangement of hollow shells.

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How did they do it?On a rainy day, Sankhya and Ganith were playing a game in theveranda. "Can you guess how far that wall is from here?" askedGanith.

"15 feet?" estimatedSankhya.Ganith measured thedistance by putting onefoot ahead of the other,and said, "Sorry, sister, it's10ft."

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'~Iright, can you guess howmany jaans wide that doorway

is?"asked Sankhya.'And what's a jaan?""The average length of an outstretched palm. Now tell me, howmany jaans?""Six," said Ganith, looking at his stretched palm first, and then atthe doorway.Sankhya ran up to the doorway, and measured with her palm."You're right! How did you guess?""I'm a genius, you know!" he answered.Actually the wily fellow had measured the floor tile in front ofhim. The doorway was three tiles across. Ganith had checkedthat each tile measured two jaans , the rest was simple!

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Ancient astrologers and mathematicians calculated distancesalmost accurately although they hadvery few tools for calculation.They certainly did not have a calculator.The Indian mathematician Aryabhatta calculated that a day has23hours, 56 minutes, 4 seconds and a fraction.Modern scientistswith sophisticated scientific measurement tools

have found the length of the day to be 23 hours, 56 minutes, 4seconds and 0.091 fractions!More than 600 years ago, Saayana,a scholar in the court of KingBukka I of the Vijayanagar Empire, calculated the speed of lightto be 2202 yojanas in half a nimisha . Converting the units yojanasand nimishas , we get 186,413.22 miles per second.Modem ca1culationsavefound it to be 186,300.00milesper second.A yo ja na is a Vedic m ea sure of dis ta nce used in a ncien t In dia . The len gth of oney oja n a is a pp ro xim a te ly 1 4-1 5 k ilom etre s.A n im ish a is a V edic m ea sure of tim e. It is equa l to 16/75 of a s eco nd .I n im isha =0.2 second

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Indian scientists and mathematicians could also calculate tinysizes.How small is an atom?

Look at the tip of a single strand of your hair. Imagine dividing thattip into hundred equal parts. Imagine one of those parts dividedinto hundred parts.That is the size of an atom!This explanation was found in the Upanishads, an ancient Indiantext. Now we know it as one centimetre divided by 100000000.Have you seen the conversion table given at the beginning ofmost diaries?The day Sankhya's Uncle Guna presented her with a diary, shespent the whole day reading all the information given in the table.She did not understand most of the things. She decided to writedown at least the few things she did understand!

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Here is Qankhya's table:

What you can New Unit Old Unit Connection betweenmeasure UnitsLength (big) Kilometre Mile 1 mile = 1.8 KilometresLength (small) Centimetre Inch 1 inch = 2.5 CentimetresVolume Litre Gallon 1gallon = 1.5 LitresMass Kilogram Pound 1 kilogram = 2.2 Pounds

What you can measure Units of MeasurementSound Decibels = dBSpeed Kilometres per hour = Kmph.Power Kilowatts = KWTemperature Degree Celsius = CElectricity Volts = V

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I. Which is longer - I mile or I kilometre?2. When you whisper in class your sound measures 20 dB.Rustling leavesmake asound of IOdB.If amotorbike makesSOdBof sound, how much louder is it than your whisper?

3. There is a fish-like creature in oceans called the ElectricEel. It produces 650 volts of electricity from the muscles inits tail. It usesthis to stun its prey. This is nearly three timesas powerful as the electricity in many of our homes! Howmany volts is that?

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Zzero goes to the River

Zzero's head starts zooming when people talk about very bignumbers or very small numbers. He does not want to measurethe distance from his house to the moon. But he likes to measureshorter distances.

Do you know we can measurethe width of a river without even

crossing the river or using ameasuring instrument, Zzero?

This is how Eka explained it to Zzero:

f A. . . . . -.-- - ---

Pick out a point across the river, such as a tree (A).21r


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Drive a stake (8) into the ground on your side of the river in linewith the tree.

~-~~ 50 fV\

Walk parallel to the riverbank up to any convenient length, say50 metres.

" ' - - __ .A.. . . . . ~ ~ . . . .~B J i > c 25Mtf)Drive a stake (C) into the ground.Continue along the bank in the same direction for half the firstdistance you measured (25 metres).

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~a ~C ~DiMark the spot D.Turn 90 degrees. Your back will now be to the river. Walk awayfrom the river until you can see your stake C such that it is in linewith the tree across the river.

Mark the spot E.Measure the distance between the stakes D and E.Measure DE.Double this distance and you will have a fairly accurate estimate,as long as your sighting measurements and angles are correct.AB = 2 X DE metres.Now you know how wide the river is without actually crossingthe river!Ancient mathematicians used techniques like these to find thedistance of faraway objects like the Sun and Moon from Earth.

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Tree Time

Climb up with a measuringtape, hold one end of the tape,and ask a friend to read the

measurement at the base of thetree!

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Sankhya and Ganith have started measuringEVERYTHING!You can too.

Try to come up with different ways to measure things.Measure your house.

Measure the PT Master's height.Measure your weight.Measure your dog's tail.

When you ride on a cycle, try to measure the time youtake to reach a particular destination.You may become a Cycling Champion one day!

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AnswersAnswers to 'Let's Measure' Page 5

I. I centimetre. (Instead of writing 'centimetre' we use the shorternotation 'ern') 12 cm width divided by 12 of Sankhya's fingers givesI cm.

2. 1.2cm. You can also say, Icm and 2 mm (mm is short for millimetre.10 millimetres make I cm.)

4. Ganith tried measuring with his feet. Putting one foot before theother, he walked from one corner of the room to the adjacentcorner. He had to put one foot in front of the other 15 times. Thenhe used a ruler to find the length of his foot. It measured 12 cm.The width of the room is 15 x 12= 180 cm. You can use a foldednewspaper as a measuring unit instead of your foot. Masons uselengths of thread to measure the walls.

Answers to 'Under the Banyan Tree' Page 13I. Sankhya and her friends actually tried to find the perimeter of thefamous Banyan Tree in Pune. They stretched out their hands, andcircled the tree with all its aerial roots such that each of them washolding hands with two classmates. Students then measured theirstretched arms from the palm of the left hand, across the chest tothe palm of the right hand. They found that most of their stretchedarms measured I m. (I m= 100 ern= 1000mm). The 100 studentshad to line up around the tree nearly 8 times, and only then couldthey completely cover it! Perimeter= 100students x Im x 8 times=800m!

2. Circle. According to our Pandit Vijayeswara,for a given perimeter, the circle encloses thelargest area.

3. a) Rectangle: Measure length and breadth. Perimeter = 2 timeslength + 2 times breadth.26


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b) Circle: Just measure the radius. Perimeter of a circle is calledCircumference. Circumference=2 x Pi x r. Pi is written as1f, the firstletter of the Greek word for Circle. R= radius. Pi isthe number you getwhen you divide the circumference of acircle by its diameter. It isalwaysthe same, whatever be the size of a circle. 1f= 3.14 approximately.c) Hexagon: Measure one side. Perimeter=6 times length of one side.

Answer to 'The Slow Horse Race' Page 14I. The wise old manaskedthe boys to EXCHANGE horses. Remember,the king said the prince whose HORSE comes last would be thewinner. By riding the other's horse, each prince would want to befirst, so that his horse could come last!

Answers to 'How Did They Do It' Page 20I. I mile is longer. Towalk one mile, you must walk one kilometre, thena little more than half a kilometre!

2. 4 times louder.3. 216 volts. 650 volts divided by 3.

Our homes usually have 220 volts.

Answer to 'Tree Time' Page 24I. Look out for the shadow of the tree.Drive a small stick into the floor and measure the shadow of thestick.Also, measure the height of the stake above the ground.Now measure the length of the tree's shadow.

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Compare your measurements. Ifthe shadow of the stick is doubleits height, then the shadow of the tree is double the height of the tree!If the shadow measures 20 m, the tree is 10m tall.

1m

2m

On the other hand, if the shadow of the stick is half the size of thestick, then the shadow of the tree will be half the size of the tree.If the shadow of the tree measures Sm, the tree measures 10m.

2m

5m1m

If the shadow of the tree measures Sm, the tree measures 10m.


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Hello, my name is Sonam Sonkar. I'm in class 8 and dream ofbeing in engineer. I enjoy kathak and also love beautiful clothes.Thank you for buying this book. My friends and I will get to readmany more books in our library because you bought this book.

Mala Kumar is a journalist, writer and editor based in Bangalore. Her stories forchildren have won awards from Children's Book Trust. She discovered her love forteaching while conducting non-formal workshops in mathematics in schools, usingthe day's newspaper instead of text-books.

Angie is a graphic designer and in her spare time loves to keep busy with ceramic.Upesh is an animator who collects graphic novels and catches up with alternatecinema in his spare time. Together they form 'The Other Design Studio'.


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Happy Maths 3Measurements

Happy Maths 4Time and Money

This is a mathematics book with a difference.There are more stories here than problems!

So read the stories, absorb the mix of facts and fiction andenjoy teasing your brain.Titles in this series

Happy Maths 1 Happy Maths 2Numbers Shapes and Data

For more information on all our titles please visitwww.prathambooks.org

Our books are available in English, Hindi, Tamil, Telugu,Kannada, Marathi, Gujarati, Bengali, Punjabi, Urdu and Oriya.

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Age Group: 11 - 14 yearsISBN 978-81-8263-908-9
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8057747 Happy Maths 3 English

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