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Adding, Subtracting, Multiplying and Dividing Measurements Study Guide: GED Math

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Practice problems for these concepts can be found at:

Measurement Practice Problems: GED Math

Addition with Measurements

To add measurements, follow these two steps:

1. Add like units.
2. Simplify the answer.

Example

Add 4 pounds 5 ounces to 20 ounces.

Be sure to add ounces to ounces.

Because 25 ounces is more than 16 ounces (1 pound), simplify by dividing by 16. The result is 1 pound 9 ounces.

Thus, 4 pounds 25 ounces = 4 pounds + 1 pound 9 ounces = 5 pounds 9 ounces.

Subtraction with Measurements

To subtract measurements, follow these three steps:

1. Subtract like units.
2. Regroup units when necessary.
3. Write the answer in simplest form.

For example, to subtract 6 pounds 2 ounces from 9 pounds 10 ounces, first subtract ounces from ounces. Then subtract pounds from pounds.

Sometimes, it is necessary to regroup units when subtracting.

Example

Subtract 3 yards 2 feet from 5 yards 1 foot.

From 5 yards, regroup 1 yard to become 3 feet. Add 3 feet to 1 foot. Then subtract feet from feet and yards from yards.

Multiplication with Measurements

To multiply measurements, follow these two steps:

1. Multiply like units if units are involved.
2. Simplify the answer.
Examples
1. Multiply 5 feet 7 inches by 3.
2. First multiply 7 inches by 3; then multiply 5 feet by 3. Keep the units separate.

Because 12 inches = 1 foot, simplify 21 inches: 15 ft. 21 in. = 15 ft. + 1 ft. + 9 in. = 16 feet 9 inches.

3. Multiply 9 feet by 4 yards.
4. First, change yards to feet by multiplying the number of feet in a yard (3) by the number of yards in this problem (4). 3 feet in a yard × 4 yards = 12 feet

Then multiply 9 feet by 12 feet = 108 square feet.

(Note: feet × feet = square feet)

Division with Measurements

To divide measurements, follow these five steps:

1. Divide into the larger units first.
2. Convert the remainder to the smaller unit.
3. Add the converted remainder to the existing smaller unit, if any.
4. Then divide into smaller units.
5. Write the answer in simplest form.

Example

Divide 5 quarts 4 ounces by 4.

First, divide 5 ounces by 4, for a result of 1 quart and a remainder of 1.

Convert the remainder to the smaller unit (ounces): R1 = 32 oz.

Add the converted remainder to the existing smaller unit: 32 oz. + 4 oz. = 36 oz.

Now, divide the smaller units by 4.

The answer is 1 quart 9 ounces.

Practice problems for these concepts can be found at:

Measurement Practice Problems: GED Math

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