5 / 12, 5 / 8, 2 / 5, 1 / 15, 11 / 40, 7 / 24 divide these six numbers into three groups, so that the sum of two fractions in each group is equal

5 / 12, 5 / 8, 2 / 5, 1 / 15, 11 / 40, 7 / 24 divide these six numbers into three groups, so that the sum of two fractions in each group is equal

Methods: compare the size, then the largest and smallest group, the second largest and fifth group, and the middle two groups
Compare the size to divide, trouble, with a calculator for decimals
zero point four one six
zero point six two five
zero point four
zero point zero six
zero point two seven five
zero point two nine one six
5/8 + 1/15 == 5/12 + 11/40 == 2/5 + 7/24

1,8,33,11,2,3,4,24,28,7 which are the simplest scores

1,33,8,33,11,2,8,3,4,24,28,7,5,20,5 which are the simplest scores?
A: 1 and 8 / 33, 2 and 3 / 8 are the simplest scores

If you have a fraction, if you add 1 to the numerator, it will be 2 / 7, and if you subtract 1 from the numerator, it will be 4 / 21. What's the fraction?
Even if it's an equation, and I just graduated from primary school, I don't want to use binary linear equations,

Let the molecule be x, then when the molecule is x + 1, the fraction is 2 / 7, so the denominator is (x + 1) △ 2 / 7 = (7 / 2) (x + 1) the molecule is X-1, and the fraction is 4 / 21, so X-1 = (4 / 21) × (7 / 2) (x + 1) X-1 = (2 / 3) (x + 1) multiplied by 33 (x-1) = 2 (x + 1) 3x-3 = 2x + 23x-2x = 2 + 3x = 5 (7 / 2) (x + 1) = 21 answer: this fraction is 5 / 21