Maths Riddles
What 3 positive numbers give the same answer when multiplied and added together?
1,2,3
Bob baked 100 biscuits. He became bored with decorating biscuits so he decided to vary the decoration. He tops every third busting with a nut, ices every fourth, and puts a cherry on every fifth. When he has finished all 100, what is the number of the biscuit that has all three decorations?
60
2, 6, 12, 20, ___?
30
What branch of math commonly uses letters or other symbols to represent unknown numbers?
algebra
What number do you get when you multiply all of the numbers on a telephone keypad?
0
I am a number that is divisible by both 3 and 4, and my digits add up to 9. What number am I?
29, 36, 43, 50 _?
57
Finish the sentence: Cos, Sine and
Tan
Each time a bouncy ball bounces, it bounces to half the height from which it falls. If Jack drops a ball from a building and it rises to a height of 24 meters, how high will it be on the fifth bounce?
1.5 meters
Brian is twice as old as Charlie. Three years from now the sum of their ages will be 33. How old is Charlie?
8
0, 1, 1, 2, 3, 5, 8 ___?
13
What this symbol mean?
"≥"
greater than or equal to
A wild dog swallowed a total of 105 nuts in five days. Each day he managed to eat eight more than he had on the previous day. How many nuts did he eat on the last day.
37
A father is twice as old as his son. Four years ago, the father was three times as old as his son. How old are they now?
The son is 8 years old, and the father is 16 years old.
1, 3, 2, 4, 3, 5, 4, ___?
6
What is another branch of math (not algebra) that may use math symbols? (Hint: they use symbols in their formulas/rules)
Geometry/angles
Two fathers and two sons go fishing. Each catches one fish, but there are only three fish caught. How is this possible?
The three people are a grandfather, his son (the father), and his grandson.
James is one third the age of his father, Steve. The two have a combined age of 68. How old is Steve?
51
1, 1, 2, 6, 24, ___?
120
5!
What is the 10th decimal digit of Pi?
5