Question

Use approximation to tell which fraction is greater 10/21 and 15/28

Answer 1

Consider two fractions
`(10)/(21)` and
`(15)/(28).`

1. Approximate first fraction by
`(10)/(20).` You know that

`(10)/(20)=(1)/(2)` and comparing two fractions with the same numerators, we compare their denominators. Since
`21>20,` then

`(10)/(21)<(10)/(20),\\ \\(10)/(21)<(1)/(2).`

2. Approximate the second fraction by
`(14)/(28).` You know that

`(14)/(28)=(1)/(2)` and comparing two fractions with the same denominators, we compare their numerators. Since
`15>14,` then

`(15)/(28)>(14)/(28),\\ \\(15)/(28)>(1)/(2).`

You have two fractions, the first one is less than
`(1)/(2)` and the second one is greater than
`(1)/(2).` Thus,

`(10)/(21)<(15)/(28).`

Answer:
`(10)/(21)<(15)/(28).`