+10
-10
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Mental Math
Quick Facts
100

36+10=?

46

100

78-10?

68

100

How many tens are in the number 93?

9

100

23+10=

33

100

10+5=

15

200

59+10=?

69

200

93-10=?

83

200

How many tens are in the number 65?

6

200

40+10=

50

200

10+4=

14
300

77+10=?

87

300
45-10=?

35

300

How many tens are in the number 22?

2

300

33+10=

43

300

10+4+10=

24

400

27+10=?

37

400

25-10=?

15

400

How many tens are in the number 79?

7

400

56+10=

66

400

10+10+10+10=

40

500

57+10=?

67

500
99-10=?

89

500

How many ones are in the number 89?

9

500

78+10=

88

500

10+5+5+10+5+5+10=

50

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