Mental Math
Picture It
AL Zebra
Potpourri
"Pun"ishment
100
Three-fourths of five-sixths is this number.
What is five-eighths (5/8)?
100
Find the missing number.
What is 3?
(The numbers under the line are the average of the three numbers in the column above.)
100
Solve for x if two x plus three equals four x minus five.
What is 4? (x=4)
100
Reducing the radius of a sphere by half reduces its volume by this much.
What is one-eighth (1/8)?
100
The shape of an empty bird cage.
What is a Polly-gon?
200
The sum of prime numbers between twenty-five and thirty-five.
What is sixty? (29+31)
200
These three pins must be knocked over to score exactly 100 points.
What are 13, 39 and 48?
200
Sanjay’s calculator is broken so he needs to buy a new one. He has two options: a calculator with an original price of $12.00 that is on sale for 10% off, and a calculator with an original price of $15.00 that is on sale for 25% off. If he buys the cheaper calculator, he pays this amount.
What is $10.80?
200
The product of the least common multiple and the greatest common divisor of 18 and 12 is this perfect cube.
What is 216? (63)
200
The circumference of a jack-o-lantern divided by its diameter.
What is Pumpkin Pi?
300
When you survey everyone in a room, fourteen people like video games and nineteen like television. Twenty-seven like neither and twelve like both, then the number of people in the room is…
What is 48 people? (14+19-12+27)
300
The missing digit of the score is ….
What is 6?
(The difference in scores forms the following series: -2, +4, -6, +8, …)
300
If four chickens can lay nine eggs in six days, this is the number of days it would take six chickens to lay sixty-three eggs.
What is 28 days?
300
A haunted house has six windows. Casper the ghost wants to enter the house by one window and leave by a different window. The number of different ways he can do this is…
What is 30 ways?
300
Baby parabolas really like this “food”.
What is the quadratic formula?
400
Number of positive integers less than 50 divisible by 3 or 8, but not by both.
What is 18? (16 + 6 - 4)
400
The number of triangles in this figure.
What is 23?
400
Nick says: “Two years ago, I was three times as old as my brother was. In three years’ time, I will be twice as old as my brother. I am ______ years old now”.
What is 17 years old? (And his brother is 7 years old)
400
Two different numbers are randomly selected from the set −2,−1,0,3,4,5 and multiplied together. The probability that their product is zero is….
What is 1/3?
400
This “Mustang Math” set of points lying on a line segment remind you of running horses.
What is a Cantor Set?
500
The number of different ways of making $20 using an unlimited supply of $10 bills, $5 bills and $1 bills.
What is 9 ways?
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500
A point is scored when the ball lands on an orange square. Give the coordinates of the last square that should be orange.
What is 6F?
(Points are scored on intersections where the number corresponds to the letter’s position in the alphabet)
500
Consider an arithmetic sequence of real numbers with common difference -3. Let the sum of the first n terms be denoted by Sn. If S4 = 10, the value of S7 is...
What is -14?
(First term is 7)
500
The sum of the number of edges on a cube, vertices on a tetrahedron, and faces on an icosahedron.
What is 36? (12 + 4 + 20)
500
A bird that likes to do combinatorial math.
What is a fact-oriole?
