Rooms of the House 5th grade-Unit 4. Practice Practice together, then individually.
Multiplying and dividing pronumerals Write the numbers together and then the pronumerals together,...
-
Upload
gerard-doyle -
Category
Documents
-
view
213 -
download
1
Transcript of Multiplying and dividing pronumerals Write the numbers together and then the pronumerals together,...
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