a + 190 + 190 : 10 = 300
a + 190 + 19 = 300
a = 300 - 19 - 190 → metoda mersului invers
a = 281 - 190
a = 91
575 - b × 32 - 45 = 50
575 - b× 32 = 50 + 45
575 - b × 32 = 95 b × 32 = 575 - 95
b × 32 = 480
b = 480 : 32
b = 15
c - ( 600 - 315 : 9 ) = 335
c - ( 600 - 35) = 335
c - 565 = 335
c = 335 + 565
c = 900
( 100 × d - 110 ) : 39 = 10
100 × d - 110 = 10 × 39
100 × d - 110 = 390
100 × d = 390 + 110
100 × d = 500
d = 500 : 100
d = 5
