Grades 3-5 Math Problem Solving in Action_ Getting Students to Love Word Problems

Modeling Thinking ◆ 123

12

= +

3456

(^2) ⁄ (^34) ⁄ 6
(^2) ⁄ 6
(^4) ⁄ 6
Figure 7.27
Virtual Number
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Figure 7.28

The Number Grid
The number grid is an excellent tool to help students develop efficient mental
strategies. Students can initially use the number grid as a scaffold to break
apart numbers, jump to friendly numbers and add or subtract quickly. For
example, on the number grid to add to result unknown problems, students
choose a number to start with and then add. You want to teach them how
to break apart numbers and use this method to add efficiently. Let’s look at
this on a number grid. For example, you might say, Olga had 45 apples and
her mother gave her 27 more. How could we hop up the number grid easily?
Let’s think about getting to some friendly numbers. We always try to find
a 10. So we would jump 45, 55, 65... that gives us the 20. Then, we would
break up the 7 into 5 and 2... so 70 and then 72 (see Figure 7.29).

Figure 7.29

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48 49 50

51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70

71 72 73 74 75 76 77 78 79 80

81 82 83 84 85 86 87 88 89 90

91 92 93 94 95 96 97 98 99 100

In the upper elementary grades, you should use the decimal number
grid when solving word problems (see Figure 7.30).

For example, Claire decided to save her money. She saved a penny

the first day. She doubled that the next day. She then doubled that

amount the next day. How much money will she have saved on the

5th day? How many days will it take her to save a dollar?