Mental Addition and Subtraction

Mental Skills (subtraction)

Multiple Choice

How many strategies of mental addition that you learned in the previous lesson?

• 1

• 2

• 3

• 4

Mental Subtraction

Poll

Can you write down all the pairs of number that make 20?

• Yes

• No

_{Mental Subtraction}

_{Analyze the questions}

• Subtraction without regrouping(taking away single-digit)

• Taking away nearest ten (single-digit)

• Subtraction without regrouping (taking away double-digit)

Poll

Did you count using the strategies that you just learned?

• Yes

• Some

• Not at all