Mental Math
Vocabulary
Fun Facts
Riddles
Other
100

What is (81 ÷ 9) + 5?


14

100

What is a number that is divided by another called?

a dividend


100

What Roman tool helped with calculations?

Abacus

100

You bought 3 packs of pencils with 6 pencils each. How many pencils do you have?

18

100

What is 1/2 of 10?

5

200

What is (144 ÷ 12) + √81?

21

200

What do you call a number with no fractional part?

Whole Number

200

What tool did ancient Egyptians use to measure fields?

Rope With Knots

200

I’m a number. Double me and add 8, and you get 20. What number am I?

6

200

What shape is a stop sign?

an octogon

300

If today is Friday, what day of the week will it be 100 days from now?

Sunday

300

A repeating pattern of shapes that covers a plane with no gaps or overlaps?

a tesselation

300

Which mathematician helped put a man on the moon?

Katherine Johnson

300

What three-digit number has digits that add up to 6, and the middle digit is 0?

105

300

A palindrome is a number that reads the same forward and backward. For example, 1001 is a palindrome. What is the positive difference between the next palindrome and 1001?

110

400

A 5-digit code is formed using the digits 1–9, with no repetition. How many such codes are divisible by 5?

32
400

Numbers with direction

a vector

400

Who was the first woman to win a Fields Medal in mathematics?

Maryam Mirzakhani

400

A drawer contains 6 red, 5 green, and 4 blue socks. If you randomly pick two socks without replacement, what is the probability that both are green?

2/21
400

What is the golden ratio?

1.618...

500

5-Digit Codes from Digits 1–9, Divisible by 5 (No Repetition)

1680

500

Sum of their divisors equals the number itself

a perfect number

500

What is the oldest known mathematical artifact?

The Lebombo bone

500

Eight years ago, a father was five times as old as his son.
Four years from now, the father’s age will be three times his son’s age at that time.
How old are they now?

son: 20

father: 68

500

What is the sum of the angles in a pentagon?

540

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