ACT Math : How to divide odd numbers

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #2 : Integers

Choose the answer which best solves the equation below:

Possible Answers:

Correct answer:

Explanation:

There are two ways to solve this problem. First you can do so algebraically by dividing both sides by 13:

But, there is another way, which if you understand odd numbers, is even faster. Of all the answers above, only one is odd. You know, given the equation, that  must be odd--any odd number multiplied by an odd number will yeild an odd number.  If you multiply an odd number by an even number, you will get an even number. 

Example Question #1 : How To Divide Odd Numbers

Solve for  in the following equation:

Possible Answers:

Correct answer:

Explanation:

There are two ways to approach this problem:

1. Use the rule that states that any two odd numbers multiplied together will yield another odd number. 

Using this rule, only one answer is an odd number (29) which will yield another odd number (493) when multiplied by the given odd number (17).

2. Solve algebraically:

Example Question #1 : Integers

Solve for  in the follwing equation:

Possible Answers:

Correct answer:

Explanation:

There are two ways to approach this problem:

1. Use the rule that states that any two odd numbers multiplied together will yield another odd number. 

Using this rule, only one answer is an odd number (85) which will yield another odd number (7,735) when multiplied by the given odd number (91).

2. Solve algebraically:

 

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