Question

by which number we divide 1100 so we get 1.1

Answer 1

let,
the number be x.
Then,
1100÷x=1•1
x=11/10×1100
x=1210

Answer 2

Let the number be n.

n ÷ 1100 = 1.1

So you move the 1100 to the other side of the equation to get:

n = 1.1 × 1100

Do the multiplication and you will find that the number is 1210.