Post on 02-Jan-2016
description
I think of a number and add 6. My answer is negative 7, what number did I start with?
Sums and Things for Parents
Well done Lucie. How did you think that through?
Sums and Things for Parents
Negative 13
The story so far ……….
children’s recall of number facts has become more accurate and faster
children are more aware of the strategies they use to calculate
they use vocabulary correctly
they are more confident about maths
maths is more fun!
What can a numerate child do?
By the age of 11 they should :
have a sense of the size of number and where it fits into the number system
know by heart addition and subtraction facts to 20, multiplication and division facts to 10x10, doubles and halves, complements to 100, multiply and divide by 10 and 100
use what they know to figure out answers mentally
What can a numerate child do? (cont.)
calculate accurately and efficiently, both mentally and on paper, using a range of strategies
recognise when it is appropriate to use a calculator- and when it is not- and be able to use one effectively
explain their methods and reasoning using correct mathematical terms
judge whether their answers are reasonable and have strategies for checking them where necessary
The aim
The aim is for children to do mathematics in their heads, and if the numbers are too large, to use pencil and paper to avoid losing track. To do this children need to learn quick and efficient methods, including appropriate written methods.
Mathematics is foremost an activity of the mind, and written calculations are an aid to that mental activity.
The Numeracy Strategy aims to develop children’s mental strategies and then written methods that derive from and support mental methods.
Learning written methods is not the ultimate aim.
We want children to ask themselves:
Can I do this in my head?
Can I do this in my head using drawings or jottings?
Do I need to use an expanded/compact written method?
Do I need a calculator?
61 + 45 7800 – 5600
5735 + 3657 5735 + 3990
83 – 68 5002 – 4996
538 - 295 267 + 267
2.5 + 2.7 5.1 - 2.78
How do you add and subtract?
16
- 9
1
Mistakes children make:
643
+ 274
8117
803
- 526
187
…….and more:
6 10 13
76 + 47 =
76
Addition
11676
+ 40
123
+ 7
86
+10
96
+10
106
+10
116
+10
123
+7
358 + 473 =
Addition
358
+ 473
11120
700
831
358
+ 473
83111
100 + 70 + 6
+ 100 + 40 + 7
200 + 110 + 13
= 323
176 + 147 =
Addition
Subtraction
Imran has 43 conkers; he gives 24 away to his friends. How many does he have left?
43 – 24 =
4333
-10
23
-10
20
-3-1
19
19 conkers
Subtraction
Sam has saved 93p, Amy has 55p. How much more money does Sam have than Amy?
93 – 55 =
55 60
+5
93
+3
90
+30
38p more
Subtraction
8.23 – 4.55 =
3.68
8.23
8.00
5.00
4.55
+0.23
+3+0.45
Subtraction
A sports stadium holds 9010 spectators. 5643 people attend a football match. How many empty seats are there?
5643
5700
6000
9010
57
+300
+3010
3367
5643 5700 9010
+ 57 +300 +3010
3367 empty seats
6000
57 x 2 78 ÷ 2
43 x 50 742 ÷ 2
36 x 25 700 ÷ 4
18 x 15 65.5 10
8 x 19 17 ÷ 5
34 x 7 5.4 ÷ 6
How do you multiply and divide?
Mistakes children make:
76
x 8
5648
67
x 54
268
335
603 101 r 5
7 847
Multiplication
47 x 8 = x 40 78 320 56 376
37 x 46 =x 30 7
40 1200 280 14806 180 42 222
1702
……… leading to algebra at KS3
x a b
a a2 ab a
2 + ab
b ab b2
ab + b2
a2 + 2ab + b
2
(a + b)2 = (a + b) x (a + b)
(a + b)2 = a
2 + 2ab + b
2
Division
375 43 43 375
47 8 8 47
…or ‘chunking’
First on a number line 87 ÷ 7
17 873
subtract 7x10 or 7 ten times
We have subtracted seven 12 times and have 3 left
so… 87 ÷ 7 = 12 r 3
subtract 7x2 or 7 twice
-70
-14
A shop notice states that there are 87 shopping days to Christmas. How many weeks is that?
87
-70 (10 weeks)
17
-14 (2 weeks)
3
So it’s 12 weeks (and 3 days) of shopping to Christmas.
432 school children are going on an outing. If each bus takes 15 passengers, how many buses will be needed?
432 -300 (20 buses)
132
- 90 (6 buses)
42
So we need 29 buses or 28 buses and some cars!
-30 (2 buses)
12 (people left)
How can you help?
Talk about how you do maths
Give praise and encouragement
Be positive
Ask your child to explain
Make sure maths is fun!