Estimate Sum Using Benchmark Fractions Half or One - Math ... - Free Printable

Let’s solve each part step by step.

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First problem (already solved as example):

We have:
6/10 + 5/10

Compare each to 1/2:

- 6/10 > 1/2 → because 5/10 = 1/2, and 6/10 is more than that.
- 5/10 = 1/2 → exactly equal.

So one addend is greater than 1/2, the other equals 1/2 → sum must be greater than 1. ✔ Correct.

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Second problem:

3/8 + 2/7

Compare each to 1/2:

→ Is 3/8 < or > 1/2?

1/2 = 4/8 → so 3/8 < 4/8 → 3/8 < 1/2

→ Is 2/7 < or > 1/2?

1/2 = 3.5/7 → so 2/7 < 3.5/7 → 2/7 < 1/2

Both are less than 1/2 → their sum must be less than 1.

The worksheet says “The sum is less than 1.” → That matches.

Now fill in the boxes:

Left box: 3/8 ___ 1/2 → we said <

Right box: 2/7 ___ 1/2 → we said <

✔ So both boxes get “<”

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Third problem:

2/5 + 1/3

Compare each to 1/2:

→ Is 2/5 < or > 1/2?

1/2 = 2.5/5 → so 2/5 < 2.5/5 → 2/5 < 1/2

→ Is 1/3 < or > 1/2?

1/2 = 1.5/3 → so 1/3 < 1.5/3 → 1/3 < 1/2

Both are less than 1/2 → sum is less than 1.

Worksheet says “The sum is less than 1.” → Correct.

Fill in the boxes:

Left box: 2/5 ___ 1/2 → <

Right box: 1/3 ___ 1/2 → <

✔ Both boxes get “<”

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Final Answer:

For the second problem:
3/8 < 1/2
2/7 < 1/2

For the third problem:
2/5 < 1/2
1/3 < 1/2