Show:
addition
subtraction
estimation to the nearest tenth
100

26+55=?

what is 81

100

45-13=?

what is 32

100

12

what is 10

200

56+13=?

what is 69

200

66-37=?

what is 29

200

17

what is 20

300

77+47=?

what is 124

300

78-29=?

what is 49

300

33

what is 30

400

61+58=?

what is 119

400

56-48=?

what is 8

400

67

what is 70

500

84+37=?

what is 121

500

93-74=?

what is 19

500

75

what is 80