Negative 1 / 3, 2 / 8, 3 / 15, 4 / 24, 5 / 35, 6 / 48, X / Y 1. The value of X and Y 2. Write out the nth number (n is divided into odd number and even number, discuss the sign of number, expressed by n)

Negative 1 / 3, 2 / 8, 3 / 15, 4 / 24, 5 / 35, 6 / 48, X / Y 1. The value of X and Y 2. Write out the nth number (n is divided into odd number and even number, discuss the sign of number, expressed by n)

1.x=7,y=63
2. The nth number: n / [(n + 1) ^ 2-1];
When n is odd, it is negative;
When n is even, it is positive

Two fifths of 20 meters is () meters, and one half of four seventh is ()

8 M 7 / 2

Six is two-thirds of (), two fifths of (), three fourths of (), and three fifths of three fourths of a meter

6 is (9) times that of two-thirds,
Two fifths are half (four fifths),
Three quarters of (2 / 3) is one half,
Three quarters of a meter (four fifths) is three fifths