Sat Math Strategies Mini Quiz Worksheet With Answer Key (Page 4 of 4) in pdf

Sat Math Strategies Mini Quiz Worksheet With Answer Key Page 4

SAT Math Strategies Mini Quiz

Strategy: plug in real numbers. Try easy prime numbers for m and n and plug

them in, checking to see which of the answers is prime. For example, let m = 3

and n = 5. For this choice, none of the answers is prime! When you are plugging

in numbers, you need to be able to eliminate all answers except for one. If you

can only eliminate a few answers, or none at all, try diﬀerent numbers to plug in.

However, if you do eliminate some answers, you don’t need to check those particular

answers again. For this question, if you try m = 3 and n = 7 next, you will ﬁnd

that only answer B is prime, so it must be correct.

Math Teacher Solution: If m and n are prime numbers, then answer D is a

composite number and can’t be prime. Answers A and C are even: since m and n

are odd numbers, m + n is even, and m + n + 2 is even as well. Also, mn is odd,

so that mn + 1 (answer E) is even. By process of elimination, answer B is correct.

Strategy: plug in real numbers. Try easy integers for a and b and plug them

in. When the equation works, you are done! You will ﬁnd that setting a and b to

2 works, as well as setting one to 1 and the other to 4. Either way, a · b = 4.

Math Teacher Solution: Combine the fractions using a common denominator

of 6:

2a + b

= 1

so that 2a + b = 6. Since a and b are positive integers, either a = 1 and b = 4, or

a = 2 and b = 2. In either case, a · b = 4.

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Sat Math Strategies Mini Quiz Worksheet With Answer Key Page 4