Đáp án:
Giải thích các bước giải:
`a)1975 . ( - 115 ) + 1979 . 5`
`=1975.(-115)+(1975+4).5`
`=1975.(-115)+1975.5+4.5`
`=1975.(-115+5)+20`
`=1975.(-110)+20`
`=-217250+20=-217230`
`b)153 . 171 - 153 . 77`
`=153.(171-77)`
`=153.94`
`=153.(100-6)`
`=153.100-153.6`
`=15300-918=14382`
`c)199 . ( 15 . 17 ) - 199 . ( - 17 + 5 )`
`=199.255-199.(-12)`
`=199.255+199.12`
`=199.(255+12)`
`=199.267`
`=199.(300-33)`
`=59700-6567`
`=53133`
`d)-39 ( 5 - 99) + 99 ( 10 - 39 )`
`=-39.5+39.99+99.10-39.99`
`=-39.5+99.10`
`=-39.5+99.5.2`
`=-39.5+198.5`
`=(-39+198).5`
`=159.5=795`
`e)- 8 : ( -2 ) - 2 . ( - 10 : 2 ) - 7 ( 5 - 4 )`
`=4-2.(-5)-7.5+7.4`
`=4+10-35+28`
`=7`
`f)7 . [ - 6 : 2 - 15 : ( - 3 ) ] - | - 3 |`
`=7.[-3+5]-3`
`=7.2-3=14-3=11`