Fun
Using only addition, add eight 8s to get the number 1,000.
888 + 88 + 8 + 8 + 8 = 1,000. This is the kind of number riddle you can work out with times tables, or by simple logic. First, get as close to 1,000 as you can (888). From there, it’s easy to figure out the rest.
What single digit appears most frequently between and including the numbers 1 and 1,000? Hint: look for a pattern!
The most common digit is 1! Did you figure out why? Every number 1-9 appears exactly the same number of times in every ten numbers. But because we included the number 1,000, there’s an extra occurrence of the number 1. In total, the number 1 appears 301 times, and every other number appears 300 times.
A monkey is trying to climb a coconut tree. He takes 3 steps forward and slips back 2 steps downward. Each forward step is 30 cm and each backward step is 40 cm. How many steps are required to climb a 100 cm tree?
50 steps.
If there are four apples and you take away three, how many do you have?
Three apples
When my dad was 31, I was just 8 years old. Now his age is twice as old as my age. What is my present age?
When you calculate the difference between the ages, you can see that it is 23 years. So you must be 23 years old now.
In a mythical land 1/2 of 5 = 3. If the same proportion holds, what is the value of 1/3 of 10?
4
One brother says of his younger brother: “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.” How old are they each now?
One way to solve this math riddle is to use even numbers: The older brother will be twice as old as his younger brother in three years’ time. This immediately rules out the older brother currently being 8, 11, and 14, so he must be 17, and the younger brother 7. Two years ago, they were 15 and 5 respectively, and in three years’ time, they will be 20 and 10.
My twin lives at the reverse of my house number. The difference between our house numbers ends in two. What are the lowest possible numbers of our house numbers?
The lowest possible numbers for the houses are 19 and 91. The difference is 72.
It is 9 am now. Rita studies for 2 hours, takes a bath for 1 hour, and then has lunch for 1 hour. How many hours are left before 9 am tomorrow?
20 hours.
I add six to eleven, and get five. Why is this correct?
This numbers riddle is designed to trip you up! You have to think more broadly. When it is 11 a.m., adding six hours makes it 5 p.m.
A small number of cards has been lost from a complete pack. If I deal among four people, three cards remain. If I deal among three people, two remain and if I deal among five people, two cards remain. How many cards are there?
There are 47 cards. To get the answer, you need to know that there are 52 cards in a pack. Then, find the multiples of four, three, and five closest to that number, and see if any of them are the same. For example, you can deal 42, 44, and 48 cards amongst four people, which would mean 9, 5, or 1 cards is missing (with three remaining). However, the only one that works for multiples of three and five people is when five cards are missing, which gives us a total of 47 cards.
A grandfather, two fathers, and two sons went to a movie theater together and everyone bought one movie ticket each. Movie tickets cost $7.00 and their total was $21.00. How?
They purchased 3 tickets. The grandfather is also a father and the father is also a son.
Old Granny Adams left half her money to her granddaughter and half that amount to her grandson. She left a sixth to her brother, and the remainder, $1,000, to the dogs’ home. How much did she leave altogether?
This one might have tripped you up! But the trick is not to focus on the hypothetical amounts, but on the fractions: Adding one half, one quarter, and one sixth tells us that the total is a fraction of twelfths (2+4+6=12). You can also think about it as 6/12, 3/12, 2/12, which equals 11/12. If the remainder is $1,000, that must be one-twelfth, so the total is $12,000.
Scott has $28.75. He purchased three cookies that cost $1.50 each, five newspapers that each cost $0.50, five flowers for $1.25 each, and used the remainder of the cash on a pair of sunglasses. How much were the sunglasses?
$15.50.
I am an odd number; take away a letter and I become even. What number am I?
Seven. (SEVEN-S=EVEN.)