Directions: Use only the digits 1 to 7, at most one time each, fill in the boxes to create a true equation.

### Hint

What place value would you like to start with? What digits “go” together?

### Answer

Number of Unique Solutions: 20 (40 with commutative property)

1: 43 = 16 + 27

2: 43 = 17 + 26

3: 47 = 32 + 15

4: 47 = 35 + 12

5: 57 = 21 + 36

6: 57 = 31 + 26

7: 61 = 34 + 27

8: 61 = 37 + 24

9: 62 = 15 + 47

10: 62 = 45 + 17

11: 67 = 14 + 53

12: 67 = 54 + 13

13: 71 = 25 + 46

14: 71 = 26 + 45

15: 74 = 23 + 51

16: 74 = 53 + 21

17: 75 = 12 + 63

18: 75 = 13 + 62

19: 76 = 41 + 35

20: 76 = 45 + 31

Source: Eric Appleton

62=59+43

12 +15 =27

You are not supposed to use the same digit twice!

50=40+10

Zero is not a choice of digits.

17+8=25

90=14+76

90=67=23

90=34+56

90=27+63

Can’t use 0 or 9.

76=52+24

15=7+8

76=35+41

97=76+21

94=74+20

45=35+10

74=39+45

76=35+41

97=76+21

94=74+20

45=35+10

74=39+45

43=17+25

57=21+36

74=21+53

67=13+54

100=10+90

How are you supposed to explain this to a 2nd grader to solve?

I would use cards on which I would write the digits 1 to 7. Then you have to ask them questions about additions. I will try it out with my students on Zoom next Monday. I know they will enjoy. I think I’m going to make a little explanation on Explain Everything.

60=40+20

43 = 16 + 27

43=27+16

49 = 17 + 32

76 = 45 + 31

57 = 21 + 36

79 = 56 + 23

57 = 37 + 20

Who on earth is writing these questions for second graders? I am three years through my math degree and had trouble with this, let alone explaining it to my little sister.

20+20=40

30+30=60

90+80=170

180+160=250

56+32=88

86+14=100

63+34=97

47+52=99

70=40+30

43=20+23

20=10+10

64=50+14

80=35+45

40=35+5

68=45+23

39=15+24

50=26+24

70=35+35

40=35+5

67=45+22

37=15+22

50=26+24

43 = 16+27

61 = 14+47

14=12+26

16=19+35

62=43+19

71=26+45

2000 = 2x 1000

5000 = 3000 + 2000

600000000000 = 2×300000000000

17+6=23

15+6=21

43 = 16 + 27

43 = 17 + 26

47 = 32 + 15