There is no need to simplify this, it is only a sum. 21 + (10/2) - 18 = 8
21 over 70 simplifies to 3 over 10 in simplest form. To simplify, divide both the numerator and denominator by their greatest common factor which is 7.
When you simplify 8 over 10 to its lowest term, the answer is 4 over 5.
4/7
3/7
6/21 = 2/7 simplified
You can't simplify it any more.
12/21 = 4/7 in its simplest form
4/7
Yes, to 8/21
Yes. It is 21/20.
Simplified - it is 5/21