Algebra
cadabra
Shape Up!
Prime Time
Chance Encounters
Riddle Me This
100

The sum of two numbers is 10 and their difference (the larger minus the smaller) is 4. What are the two numbers?

7 and 3

100

A square has a diagonal length of 10 root 2. What is the area of square?

100

100

What is the smallest two-digit number that is both a perfect square and a perfect cube?

64

100

If you flip two fair coins, what is the probability that you get one heads and one tails (in any order)?

1/2

100

On a farm, chickens and rabbits have 30 heads and 100 legs in total. How many rabbits are there?

20

200

The product of two consecutive positive integers is 56. What are the two integers?

7 and 8

200

If you double the length of a rectangle and halve its width, how does the area change?

It stays the same

200

What is the units (ones) digit of 745?

7

200

If you roll two six-sided dice, what is the probability that the sum of the two dice is 7?

1/6

200

In a meeting, each person shakes hands with everyone else exactly once. If there were 66 handshakes total, how many people were in the meeting?

12

300

Solve the equation ∣2x−5∣=3

x=4 or x=1

300

Two triangles are similar with corresponding side lengths in the ratio 2:3. If the smaller triangle’s area is 8 square units, what is the area of the larger triangle?

18 square units

300

Find the smallest positive integer that leaves a remainder of 1 when divided by 2, a remainder of 2 when divided by 3, and a remainder of 3 when divided by 4

11

300

A bag contains 5 red marbles and 3 blue marbles. If you draw 2 marbles without replacement, what is the probability that both marbles are red?

5/14

300

What three positive numbers give the same result when multiplied together as when added together?

1,2 and 3.

400

A two-digit number is such that reversing its digits gives a number 27 greater than the original. The sum of its digits is 9. What is the original number?

36

400

A large cube 3×3×3 is painted on all faces and then cut into 27 small unit cubes. How many of the small cubes have paint on exactly one face?

6

400

Find the smallest positive integer that leaves a remainder of 2 when divided by 3, a remainder of 3 when divided by 4, and a remainder of 4 when divided by 5.

59

400

You flip a fair coin 5 times. What is the probability of getting exactly 3 heads?

5/16

400

On an island of knights (truth-tellers) and knaves (liars), you meet two people, A and B. A says, “At least one of us is a knave.” B says nothing. Is A a knight or a knave (and what is B)?

A is a knight (telling the truth) B is knave

500

The function f(x)=ax2+bx+c has roots at x=1 and x=4, and passes through the point (2,3). Find the value of a.

a=-3/2

500

A regular hexagon is inscribed in a circle with radius 6 cm. What is the total length of all the diagonals of the hexagon?

36+36root3

500

Find the smallest positive number that is divisible by 5, 6, 7, and 8 but leaves a remainder of 1 when divided by 9.

3360

500

A 3-digit number is formed at random using digits 1–9 (each digit used only once). What is the probability that the number is divisible by 5?

1/9

500

A palindrome is a number that reads the same forward and backward. How many 3-digit palindromes are divisible by 3?

30