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NS 3.1*1%7
Make reasonable
estimates when comparing larger or smaller
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numbers.
UNDERLYING SKILLS AND CONCEPTS:
counting;
more and less;
proportional reasoning readiness
Estimate to Compare Numbers
When you estimate, you guess how many.
a
K
ey Ide
If you know how many are in a part, you can
compare to estimate how many there are in all.
E x am p l E
1
There are 10 pieces of candy in this jar.
About how many pieces would fill the jar?
10?
20?
50?
A – © CSL Associates, Inc. All rights reserved.
The candy you see fills about half the jar.
So the jar will hold more than 10.
Since half the jar is full, about 10 more will fit.
So the best estimate is about 20 pieces.
E x am p l E
2
There are 21 marbles in the jar.
About how many marbles would fill the jar?
30? 60? 90?
The marbles you see almost fill the jar.
So the jar will hold more than 21.
Since the jar is almost full, only a few more will fit.
So the best estimate is about 30 marbles.
Chapter 16 – Lesson 2
page 185
Name
P RAC T I C E
Estimate. Circle the best choice.
This jar has 10 marbles.
About how many marbles
will fill the jar?
10
3
20
Math
Reasoning
5
30
50
This jar has 21 candies.
About how many candies
will fill the jar?
25
This jar has 37 buttons.
About how many buttons will
fill the jar?
10
2
100
Estimation
4
40
75
This jar has 7 marbles.
About how many marbles
will fill the jar?
30
50
70
MR 3.0
Marcy has 2 balls in the box.
She says that 10 balls will fit.
Do you agree? Explain.
No. Only about 6 balls will fit because the 2 balls
take up almost half of the box already.
page 186
Chapter 16 – Lesson 2
A – © CSL Associates, Inc. All rights reserved.
1
Name
…at home!
P RAC T I C E
Estimate. Circle the best choice.
This jar has 42 buttons.
About how many buttons will
fill the jar?
10
3
50
Math
Reasoning
5
100
20
This jar has 7 marbles.
About how many marbles
will fill the jar?
20
This jar has 10 marbles.
About how many marbles
will fill the jar?
10
2
4
50
50
100
This jar has 19 candies.
About how many candies
will fill the jar?
25
40
75
Estimation
MR 3.0
Danny has 3 oranges in the box.
He says that 10 oranges will fit.
Do you agree? Explain.
No. Only about 6 oranges will fit because the 3
oranges take up half of the box already.
page 124
Home Resource and Homework
Chapter 16 Lesson 2
A – © CSL Associates, Inc. All rights reserved.
1
MCX94TEG1Ch01_30.v8.4.1 2/19/01 19:22 Page 341
Name
P RAC T I C E
Estimate. Circle the best choice.
1
This jar has 10 marbles.
About how many marbles
will fill the jar?
10
A – © CSL Associates, Inc. All rights reserved.
3
20
Math
Reasoning
5
30
50
This jar has 21 candies.
About how many candies
will fill the jar?
25
This jar has 37 buttons.
About how many buttons will
fill the jar?
10
2
4
40
75
This jar has 7 marbles.
About how many marbles
will fill the jar?
100
Estimation
30
50
70
MR 3.0
Marcy has 2 balls in the box.
She says that 10 balls will fit.
Do you agree? Explain.
No. Only about 6 balls will fit because the 2 balls
take up almost half of the box already.
Chapter 16 – Lesson 2
Student Book Page
page 186
Name
…at home!
P RAC T I C E
Estimate. Circle the best choice.
This jar has 42 buttons.
About how many buttons will
fill the jar?
10
3
50
Math
Reasoning
5
100
20
This jar has 7 marbles.
About how many marbles
will fill the jar?
20
This jar has 10 marbles.
About how many marbles
will fill the jar?
10
2
4
50
50
100
This jar has 19 candies.
About how many candies
will fill the jar?
25
40
75
Estimation
MR 3.0
Danny has 3 oranges in the box.
He says that 10 oranges will fit.
Do you agree? Explain.
No. Only about 6 oranges will fit because the 3
oranges take up half of the box already.
page 124
Home Resource and Homework
Chapter 16 Lesson 2
A – © CSL Associates, Inc. All rights reserved.
1