71 - 9 × 3 + 16 : 4 = 48
= 71 - 27 + 4 =
= 44 + 4 =
= 48
( 15 - 6 × 2 ) + 8 × 6 = 51
= ( 15 - 12 ) + 48 =
= 3 + 48 =
= 51
36 + 8 × 3 - 6 × 7= 18
= 36 + 24 - 42 =
= 60 - 42 =
= 18
72 : 8 + ( 24 - 3 × 7 ) = 12
= 9 + ( 24 - 21 ) =
= 9 + 3 =
= 12
b × 4 × 2 = 64
b × 8 = 64
b = 64 : 8
b = 8