Adding whole tens (2 addends) numbers - sum 90 or less
The number of all possible operations is equal to 56
Solve.

10 + 30 = __________

0 + 0 = __________

60 + 30 = __________

50 + 40 = __________

10 + 0 = __________

10 + 40 = __________

0 + 90 = __________

40 + 0 = __________

10 + 80 = __________

20 + 50 = __________

30 + 40 = __________

50 + 20 = __________

60 + 10 = __________

0 + 70 = __________

20 + 60 = __________

20 + 10 = __________

20 + 0 = __________

0 + 50 = __________

20 + 70 = __________

0 + 20 = __________

40 + 50 = __________

30 + 10 = __________

30 + 30 = __________

90 + 0 = __________

80 + 10 = __________

70 + 0 = __________

10 + 70 = __________

50 + 30 = __________

50 + 30 = __________

10 + 20 = __________

40 + 40 = __________

60 + 20 = __________

70 + 10 = __________

20 + 40 = __________

70 + 20 = __________

30 + 20 = __________

10 + 10 = __________

0 + 80 = __________

0 + 40 = __________

10 + 50 = __________

0 + 10 = __________

60 + 0 = __________

80 + 0 = __________

0 + 60 = __________

50 + 0 = __________

30 + 60 = __________

50 + 10 = __________

10 + 60 = __________

30 + 50 = __________

30 + 0 = __________

40 + 30 = __________

0 + 30 = __________

40 + 20 = __________

20 + 30 = __________

40 + 10 = __________

20 + 20 = __________




Adding whole tens (2 addends) numbers - sum 90 or less
The number of all possible operations is equal to 56
The answer.

10 + 30 = 40

0 + 0 = 0

60 + 30 = 90

50 + 40 = 90

10 + 0 = 10

10 + 40 = 50

0 + 90 = 90

40 + 0 = 40

10 + 80 = 90

20 + 50 = 70

30 + 40 = 70

50 + 20 = 70

60 + 10 = 70

0 + 70 = 70

20 + 60 = 80

20 + 10 = 30

20 + 0 = 20

0 + 50 = 50

20 + 70 = 90

0 + 20 = 20

40 + 50 = 90

30 + 10 = 40

30 + 30 = 60

90 + 0 = 90

80 + 10 = 90

70 + 0 = 70

10 + 70 = 80

50 + 30 = 80

50 + 30 = 80

10 + 20 = 30

40 + 40 = 80

60 + 20 = 80

70 + 10 = 80

20 + 40 = 60

70 + 20 = 90

30 + 20 = 50

10 + 10 = 20

0 + 80 = 80

0 + 40 = 40

10 + 50 = 60

0 + 10 = 10

60 + 0 = 60

80 + 0 = 80

0 + 60 = 60

50 + 0 = 50

30 + 60 = 90

50 + 10 = 60

10 + 60 = 70

30 + 50 = 80

30 + 0 = 30

40 + 30 = 70

0 + 30 = 30

40 + 20 = 60

20 + 30 = 50

40 + 10 = 50

20 + 20 = 40