GRE Math : How to subtract decimals

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #1 : Decimals

\(\displaystyle x > 0\)

Quantity A: \(\displaystyle x-1\)

Quantity B: \(\displaystyle 1-x\)

 

Possible Answers:

The relationship cannot be determined.

The two quantities are equal.

Quantity B is greater.

Quantity A is greater.

Correct answer:

The relationship cannot be determined.

Explanation:

Use the values of .5 and 2 as possible x values. If x = 2, Quantity A is positive and greater, but if x = .5, Quantity A is negative and therefore smaller. As such, the relationship cannot be determined.

Example Question #11 : Decimals

Solve for \(\displaystyle x\):

\(\displaystyle x + 0.238 = 0.999\)

Possible Answers:

\(\displaystyle x = 0.861\)

\(\displaystyle x = 0.761\)

\(\displaystyle x = 0.981\)

\(\displaystyle x = 0.771\)

\(\displaystyle x = 0.781\)

Correct answer:

\(\displaystyle x = 0.761\)

Explanation:

To solve for \(\displaystyle x\), subtract \(\displaystyle 0.238\) from both sides of the equation.  \(\displaystyle 0.999 - 0.238 = 0.761\), therefore, \(\displaystyle x = 0.761\).

If you have trouble subtracting the decimals, you can multiply both of them by \(\displaystyle 1000\) to get whole numbers, then subtract as normal, then divide your result by \(\displaystyle 1000\)

Example Question #2 : Decimal Operations

\(\displaystyle 0.327+\left(\frac{3}{8}-(0.048+2.176)\right)=?\)

Possible Answers:

\(\displaystyle 1.242\)

\(\displaystyle 0.793\)

\(\displaystyle 0.0532\)

\(\displaystyle -1.522\)

Correct answer:

\(\displaystyle -1.522\)

Explanation:

Make sure to follow the order of operations. Begin by combining all terms inside the parentheses:

\(\displaystyle 0.327+\left(\frac{3}{8}-(0.048+2.176)\right)=\)

\(\displaystyle 0.327+\left(\frac{3}{8}-(2.224)\right)\)

Convert the fraction to a decimal and once again complete the operations inside the parentheses:

\(\displaystyle \frac{3}{8}=0.375\)

\(\displaystyle 0.327+(0.375-2.224)\)

\(\displaystyle 0.327+(-1.849)\)

\(\displaystyle =0.327-1.849\)

\(\displaystyle =-1.522\)

The answer is \(\displaystyle -1.522\).

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