Question

...........must be added to
-1/4
to get
2/7​

Answer 1

if

-1/4+ x = 2/7

then,

x = 2/7-(-1/4)

Lcm of 4,7 is = 28

x = 8/28- (-7/28)

x = 15/28

so 15/28 must be added to -1/4to get 2/7

I hope it will be helpful to you