Question

Describe and correct the error in finding the sum.

3/10 + (- 1/10) = 3+1/10 = 4/10 = 2/5

Answer 1

You took 10 as LCM for the first two terms but the second term is negative

In your second step you have taken a positive sign
Second step must be
(3-1)/10

Answer 2

4/10+(-1/10)=3+1/10=4/10=2/5