Multiplying and dividing pronumerals

Write the numbers together and then the pronumerals

together, then simplify

What we know already about multiplicationIs 3x4 = 4x3 ?Is 2x3x2 = 2x2x3 ? (we can change the order when we

multiply)

If it doesn’t matter which order we multiply, we can move numbers and letters around without changing the answer.

YES!

YES!

We have a shorthand for writing numbers and letters when they are multiplied together.

6 x c = 6c 6 x c = c x 6 = c6(but mathematicians almost never

write the letter first)

Is 2xa = ax2 = 2a ?

If a = 4, is 2 x 4 = 4 x 2?

YES!

Example

6 x 3c= 6 x 3 x c= 18 x c= 18c

Example 2

• 11e x 6f• = 11 x 6 x e x f• = 66 x e x f • = 66ef

Example 3

5d x -2c x e x 4=5 x d x -2 x c x e x 4=5 x -2 x 4 x d x c x e= -10 x 4 x d x c x e= -40 x d x c x e=-40dce

Division• remember divide is the opposite to multiply

eg. 10 ÷ 5 = 2 And 2 x 5 = 10

• 10a ÷ 5a• = 10 x a 5 x a• = 10 x a (cancel out)

5 x a• = 2

1 = 2