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

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

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

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

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.

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

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?

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