Let the number is 100
If it Increased 20% then
100 × 20 ÷ 100 = 20
Increased number is 100 + 20 = 120
Now it will decrease 10 % then
120 × 10 ÷ 100 = 12
Decreased number is 120 - 12 = 108
Now
108 - 100 = 8
It means that 100 increased 8.
Increased present is 8 %
I hope it's helpful for you. Thank you