Show:
Addition without Attics
Addition with Attics
Subtraction without Borrowing
Subtraction with Borrowing
Mystery Problems
100

20+31

51

100

32+39

71

100

60-20

40

100

60-35

25

100

8+8

16

200

94+5

99

200

55+27

82

200

55-41

14

200

54-36

18

200

20+20

40

300

50+40

90

300

28+26

54

300

98-25

73

300

32-26

6

300

91-75

16

400

100+6

106

400

56+49

105

400

62-51

11

400

58-49

9

400

45+46

91

500

100+56

156

500

66+44

110

500

85-23

62

500

82-53

29

500

365+421

786