Math Skill: Mental Addition and Subtraction to 100

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View Lesson | View Sample Problems | Do Worksheet

Mental Addition and Subtraction to 100

You must know fast addition and subtraction to master this topic.
To review, see the Fast Addition and Fast Subtraction topics.

When adding or subtracting 10, just calculate the tens column.
If you borrow or carry, then calculate the hundred column.

Example 1: Addition

38
+10

48

52
+10

62

90
+10

100

Example 2: Subtraction

44
-10

34

74
-10

64

98
-10

88

#	Correct Answer	Your Answer
1	39 + 10 =
Solution

#	Correct Answer	Your Answer
2	26 + 10 =
Solution

#	Correct Answer	Your Answer
1	90 + 10 =
Solution 1 90 + 10 100

#	Correct Answer	Your Answer
2	38 + 10 =
Solution

#	Correct Answer	Your Answer
1	15 - 10 =
Solution

Complexity=40, Mode=add

Complexity=90, Mode=add

Complexity=40, Mode=sub

Complexity=90, Mode=sub

Complexity=40