Increases. However, put this question is Physics next time
Gobi desert; yellow sand; yellow river
To add fractions with different denominators you must convert the denominators into the lowest common factor. Aka the multiple they all go into. You then times the numerator by what you timsed the denominator by to make sure they both have the same denominator.
Example:
2/5+4/10
They both go into 10.
4/10+4/10= 8/10. 2 became 4 because 5x2=10.
I hope this helped!
You could also simplify 8/10 into 4/5z
By rename do you mean turn into an improper fraction?
if so, it is because without turning it into an improper fraction, you cannot subtract 3/4 from 1/4 because you would get a negative answer and that would be incorrect