870 - x : 11 x 87 = 261
x : 11 x 87 = 870 - 261
x : 11 x 87 = 609
x : 11 = 609 : 87
x : 11 = 7
x = 7 x 11
x = 77
x : 0.25 x 2.3 = 6.9
x : 0.25 = 6.9 : 2.3
x : 0.25 = 3
x = 3 x 0.25
x = 0.75
2 x (y + y) = 8.16
y + y = 8.16 : 2
y x 2 = 4.08
y = 4.08 : 2
y = 2.04
y x 1.5 + y + y x 7.5 = 59.8
y x (1.5 + 1 + 7.5) = 59.8
y x 10 = 59.8
y = 59.8 : 10
y = 5.98
m : 1/6 + m : 0.25 = 152
m : 1/6 + m : 1/4 = 152
m x 6 + m x 4 = 152
m x (6 + 4) = 152
m x 10 = 152
m = 152 : 10
m = 15.2
m : 1/3 + m : 0.25 = 1.4
m : 1/3 + m : 1/4 = 1.4
m x 3 + m x 4 = 1.4
m x (3 + 4) = 1.4
m x 7 = 1.4
m = 1.4 : 7
m = 0.2