Watch this video on how to add tidy numbers
What is a tidy number?
WALT: use different addition strategies
Addition using tidy numbers (also known as rounding and compensating)
Use the video on the slide before to help you solve the following problems using the ‘tidy numbers’ strategy. (show your working out in your books - take a photo and add to this slide)
Example a)
27 + 34 =
(+3) (-3)
30 + 31 =
Use the hundreds board if you need.
= 61
Watch this video on how to jump on a number line
What is a tidy number?
WALT: use different addition strategies
Addition using tidy numbers on a number line
Use the video on the slide before to help you solve the following problems using the number line. (show your working out in your books - take a photo and add to this slide)
Example:
You need 42 coloured pencils, but only have 27.
How many more coloured pencils do you need to buy?