I found this, Hope this helps you.
Step-by-step explanation:
Like Terms: Terms that have identical variable parts (same variable(s) and same exponent(s)). When simplifying using addition and subtraction, you combine “like terms” by keeping the "like term" and adding or subtracting the numerical coefficients.
Well you have to have the common at 50 because that it so multiply23/25 by 2 and 9/10 by 5 so 45/50 and 46/50
The diameter is twice as big as the radius