Solving addition and subtraction problems by making tidy number.

WALT - Solve addition and subtraction problems by making tidy number.

SUCCESS CRITERIA

• I can make one number to a tidy number.
• Solve the problem by either counting

forward or backward in tens.

I had $53 in my bank account and I saved $18 more.
How much money do I have?

(18 + 2 = 20) (53 - 2 = 51)   20 + 51 = 71.

Tim has $38 and his brother $27. How much money do they have in total?

(38 + 2 = 40) (27 - 2 = 25) 40 + 25 = 65.

There were 73 students in the library. Then 21 more students arrived at the library. How many students are in the library?

(73 - 3 = 70) (21 + 3 = 24) 70 + 24 = 94.

This is just part of what I did in Maths when we revise some of the addition and subtraction strategies.