Hi, I'm Dario!
I will help you learn how to work out differences between numbers in your head.
The Difference Bar is a tool that helps you find differences by breaking numbers up.
The Difference Bar
Move around the screen and select a Button.
Select and move some items like the sliders ().
Use the Tab key to move to the different elements of the screen.
Use the Shift + Tab key to move backwards through the screen.
Press the Enter or Return key to use the button that you have selected.
Use the arrow keys to move the sliders.
You can use 'round to the nearest 10' to work out the difference between 39 and 67. First, add 1 to 39 to get 40. Then, add 27 to get 67. So, the total difference is 1 + 27, which is 28.
You can use 'round to the nearest 10' strategy to help work out your answer. Or you can look another strategy in the Next hint.
You could also 'compensate' to work out the difference between 39 and 67. First, add 30 to 39 to get 69. This number is larger than 67. So, take away the extra 2 from the 30 to get the answer 28.
You can use 'compensate' strategy to help work out your difference. Or you can look another strategy in the Previous hint.