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UNDERLYING SKILLS AND CONCEPTS:
subtraction basic facts;
model hundreds, tens, and ones;
place value;
regroup hundreds to tens and tens to
ones
Subtract Two 3-Digit Numbers (two trades)
You can use place value and basic facts
to subtract 3-digit numbers.
a
K
ey Ide
E x am p l E
Find the difference between 326 and 147.
Step 1: Compare the digits in
the ones place. 6 ! 7.
You need to regroup.
B – © CSL Associates, Inc. All rights reserved.
"
3 2 6
1 4 7
"
Step 2: Regroup 1 ten for 10 ones.
Record your regrouping.
"
1 16
3 2 6
1 4 7
1 16
3 2 6 16
1 4 7 "7
9
Chapter 12 – Lesson 2
1
3 2 6
1 4 7
9
Step 5: Regroup 1 hundred for 10 tens.
Record your regrouping.
2 11
3 2 6
" 1 4 7
9
Step 3: Subtract in the ones place.
Record.
"
Step 4: Compare the digits in
the tens place. 1 ! 4.
You need to regroup.
9
Step 6: Subtract in
the tens place.
2 11
3 2 6 110
" 1 4 7 " 40
70
47 9
Step 7: Subtract in
the hundreds place.
2
1 11
3 2 6
200
1
4
7
"100
"
100
41 7 9
page 137
Name
P RAC T I C E
Subtract.
324
179
2
123
114
145
5
9
245
159
6
555
296
86
9
3
10
465
176
155
7
124
250
175
8
11
525
150
12
78
■
■
14
999 400 15
716 500 16
581 500 81
17
235
157
375
349 200 149
Number Sense
455
265
190
13
Math
Reasoning
348
224
75
289
■
■
4
198
259
352
197
354
156
MR 1.1
I am a three-digit number greater than 150 and less than 200.
Each of my digits is different.
Each of my digits is an odd number.
The sum of my digits is 9.
What number am I?
153
page 138
Chapter 12 – Lesson 2
B – © CSL Associates, Inc. All rights reserved.
1
Name
P RAC T I C E
Subtract.
235
189
2
137
128
46
5
238
147
9
6
444
185
91
9
241
186
3
543
254
55
7
260
185
221
8
11
435
170
12
225
146
265
79
■
■
449 300 149
14
777 200 577
15
681 600 81
16
616 400 216
17
375
185
190
13
Math
Reasoning
482
261
75
289
■
■
4
99
259
10
265
166
Number Sense
MR 1.1
I am a three-digit number greater than 250 and less than 300.
Each of my digits is different.
Each of my digits is an even number.
The sum of my digits is 16.
What number am I?
286 or 268
page 92
Home Resource and Homework
Chapter 12 Lesson 2
B – © CSL Associates, Inc. All rights reserved.
1
MCX94TEG2Ch01_30.v9.4.1 2/19/01 19:48 Page 253
Name
P RAC T I C E
Subtract.
1
324
179
2
123
114
145
5
9
245
159
6
555
296
86
9
352
197
354
156
10
465
176
7
250
175
124
8
11
525
150
12
235
157
375
78
■
■
349 200 149
14
999 400 599
15
716 500 216
16
581 500 81
17
455
265
190
13
Math
Reasoning
348
224
75
289
■
■
4
198
259
155
B – © CSL Associates, Inc. All rights reserved.
3
Number Sense
MR 1.1
I am a three-digit number greater than 150 and less than 200.
Each of my digits is different.
Each of my digits is an odd number.
The sum of my digits is 9.
What number am I?
153
Chapter 12 – Lesson 2
Student Book Page
page 138
Name
P RAC T I C E
Subtract.
235
189
2
137
128
46
5
238
147
9
6
444
185
91
9
241
186
3
543
254
55
7
260
185
221
8
11
435
170
12
225
146
265
79
■
■
449 300 149
14
777 200 577
15
681 600 81
16
616 400 216
17
375
185
190
13
Math
Reasoning
482
261
75
289
■
■
4
99
259
10
265
166
Number Sense
MR 1.1
I am a three-digit number greater than 250 and less than 300.
Each of my digits is different.
Each of my digits is an even number.
The sum of my digits is 16.
What number am I?
286 or 268
page 92
Home Resource and Homework
Chapter 12 Lesson 2
B – © CSL Associates, Inc. All rights reserved.
1