Page 16 - TG_G1_CH6_CHRIS

1 Less and 10 Less

Use the 100 chart. Give children red and yellow counters.
• Place a red counter on 100. Move one step to the left. Color the Say: Put one red counter on 100. Move one step to the left and color the
number red.
• Place a yellow counter on 100. Move one step up. Color the number red.
number yellow. Put one yellow counter on 100. Move one step up. Color the number yellow.
• Write the missing numbers in the spaces below. Ask: What number is just before 100? 99
What number is one up from 100? 90
1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20 What number is 10 less than 100? 90
21 22 23 24 25 26 27 28 29 30 Say: Complete the sentence.
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 ANCHOR ACTIVITY
91 92 93 94 95 96 97 98 99 100

90
99
1 less than 100 is . 10 less than 100 is . Use the Anchor Activity for this lesson as a warm-up to gauge
children’s prior knowledge and help them engage at the
beginning of class.
1.NBT.5 Given a two-digit number, mentally find 10 more or 10 less than the number without having to count, explain the reasoning used.
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TIME TO LEARN
TIME TO LEARN
1 less than 96 is 95.
1 less
I started at 96. 1 2 3 4 5 6 7 8 9 10 Give each child a copy of a 120 chart. Have them count back from 20 to 1 in
I wanted to subtract 11 12 13 14 15 16 17 18 19 20 ones.
1. I move one step 21 22 23 24 25 26 27 28 29 30
39
to the left to get the 31 32 33 34 35 36 37 38 49 40 Ask: What patterns do you see on this chart?
47
41
48
50
44
45
43
42
46
number before it. 51 52 53 54 55 56 57 58 59 60
10 less 61 62 63 64 65 66 67 68 69 70 What do you notice about rows? Each time we move one row up, we count
71 72 73 74 75 76 77 78 79 80 back 10.
85
84
I started at 96. 81 82 83 94 95 86 87 88 89 90
96
97
93
98
99 100
91
92
I want to subtract 10. 101 102 103 104 105 106 107 108 109 110 What do you notice about columns? Each time we move one step left, we
I move back 10 111 112 113 114 115 116 117 118 119 120 count 1 less.
spaces or move one What is 1 less than 96? 95
step up to get the last
ten. 1 less
10 less than 96 is 86. 10 less Using a 100 chart will develop children’s knowledge of counting. Continue
left
STEP up asking children to find 1 less and 10 less than a given numbers to ensure they
BY Write the missing number.
STEP master the concept.
1 less 10 less
1 79 80 4 108 118
Common
Common
1 less 10 less
Errors
2 30 31 5 94 104 Errors
1 less 10 less
3 99 100 6 56 66
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Children may become confused if you ask them to find 10 less of a
number greater than 100.
407