Problem Solving - the addition & subtraction connection

Is addition the opposite of subtraction?

• Yes

• No

• I don't know

25 + ______ = 145

Can a missing addend sentence be written for this problem?

Zaire sold 25 soft drinks on Monday, 30 on Tuesday and and unknown amount on Wednesday. If he sold 80 soft drinks altogether. How many did he sell on Wednesday?

• Yes

• No

• I do not know

Work it out!

Zaire sold 25 soft drinks on Monday, 30 on Tuesday and and unknown amount on Wednesday. If he sold 80 soft drinks altogether. How many did he sell on Wednesday?

• 55

• 80

• 25

How would you solve this?

Increase 34 by 72.

• Subtraction

• Multiplication

• Addition

• Division

Increase 34 by 72.

How would you solve this?

Decrease 90 by 40.

• Multiplication

• Addition

• Division

• Subtraction

Now solve it.

Decrease 90 by 40.