Hello !
1. Introduction
To compare two fractions, they must have the same denominator.
let a and d be 2 denominators
2.1 If a and d have the same denominator
1. Explanation
The easiest ! Find the fraction that has the greater numerator.
2. Example :
2/5 and 3/5
2.2 If a and d have a common multiple
1. Explanation
You just have to put the fractions with the same denominator. Multiply the smallest by the least common multiple.
2. Example :
2/5 and 3/10
2/5 = (2*2)/(5*2) = 4/10
- 4/10 > 3/10 so 2/5 > 3/10
2.3 If a and d have no common multiple
1. Explanation
We will multiply the denominators together. We also multiply the numerator because if we multiply the numerator or the denominator we necessarily multiply the other with.
2. Example :
3/7 and 4/5
The common multiple 7 : 5 = 35
(3*5)/(7*5) and (4*7)/(5*7)
15/35 and 28/35
15/35 < 28/35 so 3/7 < 4/5
3. Application
1/10 and 3/4
There is not the same divisor, nor a common multiple : It's 1.3 !
- The common multiple 10 : 4 = 20
(1*2)/(10*2) and (3*5)/(4*5)
2/20 and 15/20
- 2/20 < 15/20 so 1/10 < 3/4
4. Conclusion
1/10 < 3/4
The student is wrong!