What is 99/100 over 21 in simplest form

If you divide a fraction over a number, you can just muplitply the denominator (the number under the line) by the number by which you divide:



99 and 21 are divisible by 3, so we can divide them both by it:



but that's all we can do!

so let's multiply



and it's its simplest form

The answer is the third choice