Adjusting Addition / Subtracion

By Rebeca Muñoz San Millan

How can you do this addition?

57135

Using a number line…

+5

Counting and adjusting…

601

571 35

571

Which number do we use first? Why?

What is the nearest ten that can help me?

606

+30

What number do we end on?

Try this: 800 + 87 = (800 +

90) - 3 = 890

- 3 = 607 We need a volunteer to draw

the number line!

-30

subtraction…

576

606 35

Which number do we use first? Why?

What is the nearest ten that can help me?

571

-5

What number do we end on?

606

Now solve these:

a) 583 – 71 756 – 11 234 – 199

b) 645 + 63 572 + 19 5932 + 299

c) 584 – 97 600 - 401 368 - 199

d) 126 + 88 154 + 99 500 - 200