Question

2.5 of what is 2.21 answer

Answer 1

of usually means multiplication
is means equal
Let X be the number missing
So, 2.5 of X is 2.21
2.5 × X = 2.21
Solve for x: x=0.884

Answer 2

Do this:
2.5/x = 2.21 (Multiply by x on both sides)
2.5 = 2.21x (Divide by 2.21 on both sides)
x = 1.311221719450714 (Approximately 1.3)
And if you put 2.21(1.311221719450714) into the calculator you get 2.5
So your answer is 1.3 unless you were supposed to round to a different place
Hope this helps. Bye