a)
5 x [ 8 + ( - 2) x ( -1) - (-90)]+24= 524
= 5 × ( 8 + 2 + 90 ) + 24 =
= 5 × 100 + 24 =
= 500 + 24 =
= 524
b)
100 - {10 + 2 x [( - 5) - (-7+4)]}x(-6)+4= 140
= 100 - [ 10 + 2 × ( - 5 + 3 ) ] × ( - 6) + 4 =
= 100 - [ 10 + 2 × ( - 2) ] × ( - 6) + 4 =
= 100 - ( 10 - 4 ) × ( - 6) + 4 =
= 100 - 6 × ( - 6) + 4 =
= 100 + 36 + 4 =
= 140