SAT Math : How to add even numbers

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #1 : How To Add Even Numbers

If x represents an even integer, which of the following expressions represents an odd integer?

Possible Answers:

3x – 2

2x – 2

3x + 1

x + 2

5x + 4

Correct answer:

3x + 1

Explanation:

Pick any even integer (2, 4, 6, etc.) to represent x. The only value that is odd is 3x + 1. Any number multiplied by an even integer will be even. When an even number is added and subtracted to that product, the result will be even as well. 3x + 1 is the only choice that adds an odd number to the product.

Example Question #13 : Integers

Add:  \(\displaystyle 198+103\)

Possible Answers:

\(\displaystyle 291\)

\(\displaystyle 211\)

\(\displaystyle 301\)

\(\displaystyle 311\)

\(\displaystyle 201\)

Correct answer:

\(\displaystyle 301\)

Explanation:

Add the ones digit.

\(\displaystyle 8+3 = 11\)

Since the number is 10 or greater, the tens digit is the carryover.

Add the tens digit with the carryover.

\(\displaystyle 9+0+(1)= 10\)

Add the hundreds digit with the carryover.

\(\displaystyle 1+1+(1)=3\)

Combine all the ones digits in our calculations.

The answer is \(\displaystyle 301\).

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