Is 4/5 greater or less than 45/100? How do you know?

For now, assume 4/5 and 45/100 are equal fractions

4/5 = 45/100

4*100 = 5*45 ... cross multiply

400 = 180

Since the left side (400) is larger than the right side (180), this means that the original left side (4/5) is larger than the original right side (45/100)

We can go back to the steps above and replace every equal sign with a "greater than sign" like so

4/5 > 45/100

4*100 > 5*45 ... cross multiply

400 > 180

the third inequality is true, which confirms the first inequality must also be true

Further confirmation can be found through using a calculator to convert to decimal form

4/5 = 0.80

45/100 = 0.45

We see that 0.80 is larger than 0.45, so 4/5 is larger than 45/100.

4/5 because you have to multiply the denominator by 20 and the numerator by 20 so then you will get your answer 80/100