[ ( 100 - y / 10 ) : 10 + 5 ] : 10 = 10 / 10
[ ( 100 - y / 10 ) : 10 + 5 ] : 10 = 1
( 100 - y / 10 ) : 10 + 5 = 1 × 10
( 100 - y / 10 ) : 10 = 10 - 5
( 100 - y / 10 ) : 10 = 5
100 - y : 10 = 5 × 10
y / 10 = 100 - 50
y / 10 = 50
y = 50 × 10
y = 500 → numarul, aflat prin metoda mersului invers
Verific:
[ ( 100 - 500 / 10 ) : 10 + 5 ] : 10 = 1
= [ ( 100 - 50 ) : 10 + 5 ] : 10 =
= ( 50 : 10 + 5 ) : 10 =
= ( 5 + 5 ) : 10 =
= 10 : 10 =
= 1