Then you multiply the enumerator ( top of fraction) by the same number you multiplied the denominator

2/7 =2x6x5/7x6x5=60/210

5/6=5x5x7/6x5x7=175/210

1/5=1x6x7/5x6x7=42/210

Then you add subtract the top

60/210+175/210-42/210=193/210

If possible reduce the fraction, which you can’t in this case.

eg:

2/7+5/6 has to be converted as LCM is 7*3*2=42

so when 7 is multiply ? will get 42 is 6 so multiply 2 with 6

that is 12

when 6 is multiply by 7 we get 42 so multiply 5 eith 6 so 30

now u can add 12/42+30/42=42/42

so ans is 1

and now u subtract1/5

it is simple

1-1/5=5-1/5

so whole ans is 4/5

….That’s 60/210 + 175/210 – 42/210

Brute force method is to multiply all the demoninators together.

🙂