Today, you will be adding and subtracting a tens number to and from a two-digit number. Look up and down the columns of your 100 squares. Can you see that the tens digit changes but the ones digit stays the same? Do we need to count every square when we add or subtract a tens number?
Here is a link you can use to practise using the dienes to make your addition or subtraction calculation:
Now complete the addition and subtracting tens numbers worksheets. Afterwards, fill in the +10 and -10 sheet with the numbers given.