In a subtraction formula, the sum of the subtracted, the subtracted and the difference is 160, and the difference is three times that of the subtracted. What is the difference?

In a subtraction formula, the sum of the subtracted, the subtracted and the difference is 160, and the difference is three times that of the subtracted. What is the difference?

160÷2÷（3+1）×3
=80÷4×3
=20×3
=60

49 and 124 / 125 times (- 5)
It's easy

The original formula = (50-1 / 125) * (- 5) = - 250 + 1 / 25 = - 249 and 24 / 25
Just take the integer 50

(a + 5) times (a + 5) minus a times a = 125

（a+5）(a+5)-a*a=125
a²+10a+25-a²=125
10a+25=125
10a=100
a=10

The observation rules were filled in the blank, 1,4 / 5,6 / 10,8 / 17, --, 12 / 37

Observation rule, fill in the blank, 1 (= 2 / 2), 4 / 5, 6 / 10, 8 / 17, (10 / 26), 12 / 37,. 2n / (n ^ 2 + 1)