180 over 100 is the same as 18 over 10 which is the same as 9 over 5 which is the same as 1 and 4 over 5 (1 and a four fifths) which is the same as 1.8

180/630 can be multiplied by 0.01111.../0.01111... to simplify it to 2/7. Multiplying by 1, does not change the value of the number, and any number divided by itself equals 1.