1/10 + ? = 1
i need and i don't understand

The answer is 10 because 1 divided by 10 is 0.1 then times that by 10 and you get 1.

1 is the same as any number over itself
so 1= 10/10

so to solve for the question mark we would subtract 1/10 from both sides of the equations

1/10+?=10/10
if we subtract 1/10 from both sides that leaves us with ? on one side and 9/10 on the other side

so our equation is now ?=9/10

so ? is equal to 9/10