ai giai giup minh bai 108,111 trang 98,99 09/08/2021 Bởi Nevaeh ai giai giup minh bai 108,111 trang 98,99
Bài 108 trang 98 SGK toán 6 Đề bài Cho số nguyên a khác 0. So sánh -a với a, -a với 0 Giải. – Nếu a > 0 thì –a < a và –a < 0. – Nếu a < 0 thì –a > a và –a > 0. Bài 111 trang 99 SGK 6 Đề bài Tính các tổng sau: a) [(−13)+(−15)]+(−8)[(−13)+(−15)]+(−8) b) 500–(−200)–210−100500–(−200)–210−100 c) –(−129)+(−119)−301+12–(−129)+(−119)−301+12 d) 777–(−111)–(−222)+20 Giải. a) (–13)+(–15)+(–8)(–13)+(–15)+(–8) =–(13+5+8)=–(13+5+8) =–36.=–36. b) 500–(–200)–210–100500–(–200)–210–100 =500+200–210–100=500+200–210–100 =500+200–(210+100)=500+200–(210+100) =700–310=390.=700–310=390. c) –(–129)+(–119)–301+12–(–129)+(–119)–301+12 =129–119–301+12=129–119–301+12 =(129+12)–(119+301)=(129+12)–(119+301) =141–420=141–420 =–279.=–279. d) 777–(–111)–(–222)+20777–(–111)–(–222)+20 =777+111+222+20=777+111+222+20 =(777+111+222)+20=(777+111+222)+20 =1110+20=1130. Bình luận
Bài 108 trang 98 SGK toán 6
Đề bài
Cho số nguyên a khác 0. So sánh -a với a, -a với 0
Giải.
– Nếu a > 0 thì –a < a và –a < 0.
– Nếu a < 0 thì –a > a và –a > 0.
Bài 111 trang 99 SGK 6
Đề bài
Tính các tổng sau:
a) [(−13)+(−15)]+(−8)[(−13)+(−15)]+(−8)
b) 500–(−200)–210−100500–(−200)–210−100
c) –(−129)+(−119)−301+12–(−129)+(−119)−301+12
d) 777–(−111)–(−222)+20
Giải.
a) (–13)+(–15)+(–8)(–13)+(–15)+(–8)
=–(13+5+8)=–(13+5+8)
=–36.=–36.
b) 500–(–200)–210–100500–(–200)–210–100
=500+200–210–100=500+200–210–100
=500+200–(210+100)=500+200–(210+100)
=700–310=390.=700–310=390.
c) –(–129)+(–119)–301+12–(–129)+(–119)–301+12
=129–119–301+12=129–119–301+12
=(129+12)–(119+301)=(129+12)–(119+301)
=141–420=141–420
=–279.=–279.
d) 777–(–111)–(–222)+20777–(–111)–(–222)+20
=777+111+222+20=777+111+222+20
=(777+111+222)+20=(777+111+222)+20
=1110+20=1130.