For the simplest fraction, the denominator is multiplied by 5, and the numerator is reduced to one third of the original, and the simplified fraction is one seventh, so the original fraction can be obtained

For the simplest fraction, the denominator is multiplied by 5, and the numerator is reduced to one third of the original, and the simplified fraction is one seventh, so the original fraction can be obtained

Backward method:
Molecule: 1 × 3 = 3
Denominator: 7 △ 5
If 7 cannot be divided by 5, then 7 will be expanded by 5 times, and molecule 1 will also be expanded by 5 times, that is, 5 / 35,
Then we use the backward method: numerator: 5 × 3 = 15, denominator: 35 △ 5 = 7, the original fraction is 15 / 7

For a fraction, the numerator is reduced by three times, the denominator is expanded by two times, and the reduced fraction is one seventh?

Let the prime numerator be x and the prime denominator be y,
1 / 3x to 2Y = 1 to 7
2y=7/3x
So x / y = 6 / 7

A simplest true fraction is obtained by expanding its denominator to 4 times of the original one, reducing its numerator to 1 / 7 of the original one and then reducing it to 1 / 44
It's a very simple formula, not an equation

1/44/（1/7*1/4）=1/44*28=7/11

For a simplest fraction, the denominator is expanded to five times of the original, the numerator is reduced to one third of the original, and the simplified fraction is one seventh
The main formula

1 / 7 is obtained after the original denominator is expanded 5 times and the numerator is reduced to 1 / 3 of the original. The inverse operation is taken, that is, the denominator is reduced 5 times and the numerator is expanded 3 times, that is, 1 * 3 / (7 / 5) gets 15 / 7, which is the original simplest fraction