Addition
All the fish in a stream weigh exactly 1/2 of a pound plus 1/2 of a fish. How many pounds does each fish weigh?
One
A group of students were standing in the blazing sun facing due west on a march past event. The leader shouted at them: Right turn! About turn! Left turn! At the end of these commands, in which direction is the students facing now?
East. They will turn 90 degrees in a right turn, and they turn180 degrees in an about-turn, and finally they turn 90 degrees in a left turn. Therefore, the students are now facing east.
You are given a telephone and asked to multiply all the numbers on the device’s number pad. What will be the answer?
zero (The number pad contains number 0. When you multiply any number by zero, the answer will be zero)
Something very extraordinary happened on the 6th of May, 1978 at 12:34 a.m. What was it?
At that moment, the time and day could be written as: 12:34, 5/6/78.
You are given 3 positive numbers. You can add these numbers and multiply them together. The result you get will be the same. Which are the numbers?
1, 2, 3
How can you add eight 8's to get the number 1,000? (only use addition).
888 + 88 + 8 + 8 + 8 = 1,000
What is the maximum possible number of times you can subtract number 5 from number 25?
Only once. This is because when you subtract 5 from 25 for the first time, it becomes number 20, then 15 and so on.
If a hen and a half lay an egg and a half in a day and a half, how many eggs will half a dozen hens lay in half a dozen days?
Two dozen. If you increase both the number of hens and the amount of time available four-fold, the number of eggs increases 16 times. 16 x 1.5 = 24.
What can you put between a 7 and an 8 so that the result is greater than a seven, but less than an eight?
a decimal (7.8)
I am the only number spelled with the same amount of letters as my own value. What number am I?
Four
Raj has 2 books. One of the books is faced upside-down and the second book is rotated which makes the top of the book facing Raj. Then what will be the total sum of the 1st pages in each of these books?
2. Regardless of how the books are oriented, the first page of every book is page number 1. So 1 + 1 = 2!
Mary has 7 daughters and each of them has a brother. Can you figure out the total number of kids Mary have?
8 kids because the sisters have just one brother in common.
Two fathers and two sons sat down to eat eggs for breakfast. They ate exactly three eggs, each person had an egg. The riddle is for you to explain how.
One of the 'fathers' is also a grandfather. Therefore the other father is both a son and a father to the grandson.
In other words, the one father is both a son and a father.
I am heavy forward but backwards I'm not. What am I?
A ton
I am a number. When you add the letter "G" to me, I go away.
One (gone)
How many months of the year have 28 days?
12...they all have at least 28 days
How old is your son? asked a man to his neighbor. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.
How old is the man's son?
Five
You want to boil an minute egg for two minutes. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?
Once the water is boiling, turn the three-minute timer and five-minute timer over. When the three-minute timer runs out, put the egg in the boiling water. When the five-minute timer runs out, two minutes have elapsed and it is time take the egg out of the water. You don't need the four-minute timer for this riddle.
When does 11 + 3 = 2?
When you are telling time on a clock.
11am + 3 hours = 2pm
Tom was asked to paint the number of plates on 100 apartments which means he will have to paint numbers 1 through 100. Can you figure out the number of times he will have to paint the number 8?
20 times. (8, 18, 28, 38, 48, 58, 68, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 98)
When Grant was 8, his brother was half his age. Now, Grant is 14. How old is his brother?
His brother is 10. Half of 8 is 4, so Grant’s brother is 4 years younger. This means when Grant is 14, his brother is still 4 years younger, so he’s 10.
You are given a sequence: 1 11 21 1211 111221 312211. Can you figure out the next number in this sequence?
13112221 (Each of the number in the sequence is the description of the previous number. If you start with 1, the 2nd number is 11 (one 1), third number is 21 (two 1’s), fourth number is 1211 (one 2, one 1) and so on.
If you divide 100 by half, What will be your answer?
100 / half
Place three matches on a table. Tell a friend to add two more matches to make eight.
Add two matches to make a roman numeral eight.
VIII
81 x 9 = 801. What must you do to make the this equation true?
Turn it upside down. 108 = 6 x 18.