A= -4/7×5/2-3/2×7/9=? B= 7/15-1/15-10/7 C= -3/4+1/2 ÷ 2/5-5/2 D= 3- 2/3 ÷ 4/3×7

A= (-4/7×5/2 ) - (3/2×7/9)
A= ((-2 / 7)×5 ) - (1/2×7/3)
A= -10 / 7 - 7 / 6
A= (-60 - 49)  42
A= -109/  42


B= 7/15-1/15-10/7
B= 6/15-10/7
B= 42-150/105
B= -108/105


C= -3/4+1/2 ÷ 2/5-5/2
C= -3/4+2/4 ÷ (4-25)/10
C= -1/4 ÷ (-21/10)
C= -1/4 x  (-10/21)
C= 10 /84
C= 5 /42


D= 3- 2/3 ÷ 4/3×7
D= (9 - 2)/3 ÷ 28/3
D= 7/3 ÷ 28/3
D= 7/3 x 3/28
D= 7/28
D= 1/4