Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

Using Only Five 5's and any mathematical operator make sum as 37

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

How do you go from 98 to 720 using just one letter?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

Replace the (?) with the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

What's a single-digit number with no value?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

How many triangles are there on the puzzle below?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?