Name
_
Reteaching
9-4
Estimating Sums and
Differences of Fractions
Toestimate the sum or difference of two fractions, replace each
fraction with the nearest half or whole. You can use a number line
to check whether each fraction is closest to 0, or 1. Estimate
3
9
the sum 0f "8 + 16'
i,
i?
Step 1: -Find ~ on the number line. Is ~ closer to -0 or
3
"8
••• 1 1 1 1 1 1
o
+
1 1 1 1 1 1 1 1 1 1 ••
1
1
2
9
1 6 on
Step 2: Find
the number line. Is
1~
closer to
ior to 1? --
9
16
••. 1 1 1 1 1 1 1 1 1
o
+
1
2
1 1 1 1 1 1 1~
1
Step 3: Add to find the estimate.
t+t
=
1.
For 1 and 2, complete each sentence to help you replace each
fraction with the nearest half or whole. Use each number line to help.
1. ~ is between __
o
1
1
1
1
1
2. 156 is between __
but
is closer to -_.
i rounds to --
is closer to -_.
"'1
and __
1
1
2
1
I.
1
0(
and __
156 rounds to
but
_
I I 1 I I I I I I I I I I I I 1 I •.
1
1
o
2
For 3 through 10, estimate each sum or difference by replacing
each fraction with 0, or 1.
i,
2
3
3. 5" + 4"
7
4
1
4
4. "8- 9
5. "2 + "7
8. ~-~
924
·9+5
.•
~-.-~~----
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