group 1 math

Today in maths we were learning to solve subtraction problems using tidy numbers.  First we thought about the new strategies we had used this term that might help.  These were subtracting using place value and adding using tidy numbers.

When we add using tidy numbers, we add on one side and take away on the other side of the equals.  This is different when we subtract using tidy numbers.  When we subtract using tidy numbers we add on one side and add on the other side of the equals.

When solving a problem like 453- 289=?

First I would add 11 to 289, to make it into 300.
453 - 300 = 153
Now I need to add back on the 11 extra that I took off
153 + 11 = 164
Therefore, 453-289 = 164