Question

100 - 80 + 40 - ( 30 + 5 ) = , 45 - ( 120 - 100 ) + 130 - ( 100 + 10 ) = , ( 7 + 5 ) + [ 6 - ( 9 - 5 ) + ( 15 + 1 ) ] = , 58 + [ 48 - ( 31 - 10 ) + 15 ] =

Answer 1

Boa noite.

100 - 80 + 40 - ( 30 + 5 ) = 
100-80+40-(35) = 
100-80+40-35 = 
140-115 = 25

45 - ( 120 - 100 ) + 130 - ( 100 + 10 ) = 
45-(20)+130-(110) = 
45-20+130-110 = 
175-130 = 45

( 7 + 5 ) + [ 6 - ( 9 - 5 ) + ( 15 + 1 ) ] = 
12+[6-(4)+(16)] = 
12+[6-4+16] = 
12+[22-4] = 
12+18 = 30

58 + [ 48 - ( 31 - 10 ) + 15 ] = 
58+[48-(21)+15] = 
58+[48-21+15] = 
58+[63-21] = 
58+42 = 100

Bons estudos! :-)