You need to arrange three 7 and mathematical symbols to form number 1?

What is next number in the pattern below:

131 517 192 123 ?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

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

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111