Download Mental Math – 5th Grade

Mental Math – 5th Grade
1. What is the positive difference between the lengths of the radii of two circles: one with a
circumference of twenty pi, and the other with a circumference of twelve pi?
2. What is the product of thirty-four and twelve?
3. If there are twelve blue calculators, eight red calculators, and six silver calculators, what is
the probability that a randomly selected calculator is blue? Express your answer as a reduced
fraction.
4. A boy has a fever of “one hundred and two point four” degrees. After taking medicine, it
decreases “zero point two” degrees each hour. After how many hours will his temperature be
“ninety-eight point six” degrees?
5. If the sum of x, one-half, and two-thirds is two, what is the value of x? Express your answer
as a reduced fraction.
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6. The vertex angle in an isosceles triangle has a measure of twenty degrees. What is the degree
measure of the largest angle in the triangle?
7. What is the average of the numbers three, twenty-five, twenty, seventeen, and zero?
8. Sally Sue skip-counted by threes, starting with the number twelve. What number will Sally
Sue say eighth?
9. The product of three prime numbers is one hundred fifty-four. What is the sum of those three
numbers?
10. For what value of Q is the following equation true? “Three Q plus fifteen equals twenty-four.”
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11. What is the sum of three-ninths of twenty-seven and seven-eighths of fifty-six?
12. What is the positive difference of the decimal “twenty-three and four tenths” and the decimal
“three and thirty-nine hundredths”? Express your answer as a decimal.
13. A rope that measures four yards in length has four inches cut off from one of its ends. How
long, in inches, is the rope now?
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14. If six times a number is equal to nine more than three times the same number, what is the
number?
15. An unfair coin has a twenty-five percent chance of landing on heads and a seventy-five percent
chance of landing on tails. If the coin is flipped twice, what is the probability of flipping one
head and one tail? Express your answer as a reduced fraction.
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16. If you started solving this mental math problem at “nine twenty-four A.M.” and finally finished
at “eleven nineteen A.M.” on the same day, for how many minutes were you working on this
difficult problem?
17. What is the positive difference between the square root of four hundred forty-one and the
square root of sixty-four?
18. When rolling two standard, fair six-sided dice, what is the probability that the sum of the
two numbers rolled is three? Express your answer as a reduced fraction.
19. If you start with six hundred chocolate chips, use sixty-two in one recipe, and then one hundred
eighty-four in another recipe, how many chocolate chips will you have left?
20. If the area of a rectangle is thirty-six and one of the side lengths is twelve, what is the perimeter
of the rectangle?