Bài 1:
a, ... Dấu +
b, ... Dấu -
Bài 2:
a, 15. ( - 2). ( - 5). ( - 6)
= 15.( -2.-5.-6)
= 15.( -60)
= -900
b, 4.7. ( - 11) . ( - 2)
= 28.22
= 616
Bài 3:
a, ( 37-17).( -5)+23.( -13-17)
= 20.( -5)+23.( -30)
= -100-690
= -790
b, -57.( 67-34)-67.( 34-57)
= -57.67+57.34-67.34+67.57
= 34.( 57-67)
= 34.( -10)
= -340
Bài 4:
a, ( -4).125.( -25).( -6).( -8)
= [ ( -4).( -25)].[ 125.( -8)].( -6)
= 100.( -1000).( -6)
= 600 000
b, -98.( 1-246)-246.98
= -98+246.98-246.98
= -98
