How can you write 1 9/100 in a decimal

1 9/100

= 1 + 9/100

= 1/1 + 9/100

= (1/1 * 100/100) + 9/100

= 100/100 + 9/100

= 109/100

= 109 ÷ 100

= 1.09

Whenever you see a fraction ... like  9/100 ... it means a division problem.

A fraction means
                               (the top number) divided by (the bottom number) .

If you just pull out your pencil or your calculator and actually
do the division, the quotient you get is the decimal form of
the fraction.

If you divide  9  by  100, you get  0.09 .

So  (1  and  9/100)  is the same thing as  1.09 .