How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

I am an odd number. Take away a letter and I become even. What number am I?

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

I am a number I am not an odd number I am higher than 90 I am not higher than 100 If you subtract me from 100, you get nothing. What number am I?