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NS 2.3*1%7
Use mental
arithmetic to find the sum or difference of two twoVXEWUDFWRUIURPDJLYHQQXPEHU±
UNDERLYING SKILLS AND CONCEPTS:
digit numbers.
counting;
number patterns
Use Mental Math:Ten More,Ten Less
You can use a hundred chart
to find numbers that are ten
more and ten less than a
given number.
K
a
ey Ide
E x am p l E
1
Write the number that is
ten more than 75.
85
1
2
3
4
5
6
7
8
9 10
11 12 13 14 15 16 17 18 19 20
B – © CSL Associates, Inc. All rights reserved.
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
E x am p l E
2
Write the number that is
ten less than 60.
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
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
Chapter 4 – Lesson 2
page 41
Name
P RAC T I C E
Write the number that is ten more.
1
29
_______________
39
2
31
_______________
41
3
33
_______________
43
4
32
_______________
42
5
34
_______________
44
6
36
_______________
7
279
_______________
289
8
281
_______________
291
9
283
_______________
10
413
_______________
423
11
415
_______________
425
12
417
_______________
46
293
427
Write the number that is ten less.
13
55
_______________
45
14
53
_______________
43
15
51
_______________
16
81
_______________
71
17
79
_______________
69
18
77
_______________
19
90
_______________
80
20
88
_______________
78
21
86
_______________
22
264
_______________
254
23
262
_______________
252
24
260
_______________
25
Logic
67
76
250
MR 1.1
Tim is 10 years older than Ben.
Ben is one year younger than Erin.
Erin is 7 years old.
How old is Ben?
How old is Tim?
page 42
Ben is 6.
Tim is 16.
Chapter 4 – Lesson 2
B – © CSL Associates, Inc. All rights reserved.
Math
Reasoning
41
Name
P RAC T I C E
Write the number that is ten more.
1
39
_______________
49
2
21
_______________
31
3
35
_______________
45
4
46
_______________
56
5
63
_______________
73
6
58
_______________
7
284
_______________
294
8
162
_______________
172
9
365
_______________
10
314
_______________
324
11
426
_______________
436
12
242
_______________
68
375
252
Write the number that is ten less.
13
45
_______________
35
14
26
_______________
16
15
36
_______________
16
61
_______________
51
17
88
_______________
78
18
57
_______________
19
80
_______________
70
20
42
_______________
32
21
74
_______________
22
335
_______________
325
23
149
_______________
139
24
220
_______________
25
Logic
47
64
210
MR 1.1
Jerry is 10 years older than Bob.
Bob is one year younger than Roy.
Roy is 8 years old.
How old is Bob?
How old is Jerry?
page 28
Bob is 7.
Jerry is 17.
Home Resource and Homework
Chapter 4 Lesson 2
B – © CSL Associates, Inc. All rights reserved.
Math
Reasoning
26
MCX94TEG2Ch01_30.v9.4.1 2/19/01 19:44 Page 77
Name
P RAC T I C E
Write the number that is ten more.
1
29
_______________
39
2
31
_______________
41
3
33
_______________
43
4
32
_______________
42
5
34
_______________
44
6
36
_______________
7
279
_______________
289
8
281
_______________
291
9
283
_______________
10
413
_______________
423
11
415
_______________
425
12
417
_______________
46
293
427
B – © CSL Associates, Inc. All rights reserved.
Write the number that is ten less.
13
55
_______________
45
14
53
_______________
43
15
51
_______________
16
81
_______________
71
17
79
_______________
69
18
77
_______________
19
90
_______________
80
20
88
_______________
78
21
86
_______________
22
264
_______________
254
23
262
_______________
252
24
260
_______________
Math
Reasoning
25
Logic
41
67
76
250
MR 1.1
Tim is 10 years older than Ben.
Ben is one year younger than Erin.
Erin is 7 years old.
How old is Ben?
How old is Tim?
Chapter 4 – Lesson 2
Ben is 6.
Tim is 16.
Student Book Page
page 42
Name
P RAC T I C E
Write the number that is ten more.
1
39
_______________
49
2
21
_______________
31
3
35
_______________
45
4
46
_______________
56
5
63
_______________
73
6
58
_______________
7
284
_______________
294
8
162
_______________
172
9
365
_______________
10
314
_______________
324
11
426
_______________
436
12
242
_______________
68
375
252
Write the number that is ten less.
13
45
_______________
35
14
26
_______________
16
15
36
_______________
16
61
_______________
51
17
88
_______________
78
18
57
_______________
19
80
_______________
70
20
42
_______________
32
21
74
_______________
22
335
_______________
325
23
149
_______________
139
24
220
_______________
25
Logic
47
64
210
MR 1.1
Jerry is 10 years older than Bob.
Bob is one year younger than Roy.
Roy is 8 years old.
How old is Bob?
How old is Jerry?
page 28
Bob is 7.
Jerry is 17.
Home Resource and Homework
Chapter 4 Lesson 2
B – © CSL Associates, Inc. All rights reserved.
Math
Reasoning
26