SQL Script for comman denominator

Hi Experts,
Can you please help me to write script to calculate values for New numerator and new denominator

Table Name : tbl_calc

Numerator Denominator New Numerator New denominator
1 2 2 4
1 4 1 4
1 4 1 4

Something like below
½ + ¼ + ¼ = 2/4 +1/4 +1/4 = 1