文档介绍：计算:(口答)
(1) –2
2
2
(3) (2×3)
2
(2) 2×3
1
3
(4) –1+ ×(-3)
= - 4
= 18
= 36
= – 2
计算
11
5
11
3
1
3
1
2
5
4
-
( )
×
×
×
(1)加法交换率: a+b=b+a
(2)加法结合率: (a+b)+c=a+(b+c)
(3)乘法交换率: ab=ba
(4)乘法结合率: (ab)c=a(bc)
(5)乘法分配率: a(b+c)=ab+ac
运算顺序:
先算乘方,再算乘除,最后算加减。
如有括号,就先算括号里面的。
=-
1
8
计算
(-2)2-(-52)×(-1)5+87÷(-3)×(-1)4
解: (-2)2-(-52)×(-1)5+87÷
(-3)×(-1)4
=4-(-25)×(-1)+87÷
(-3)×1 (先乘方)
=4-25-29 (再乘除)
=-50 (最后相加)
注意: (-2)2=4, -52=-25, (-1)5=-1, (-1)4=1
计算:-10-8÷(-2)-(-4)×(-3)
解: -10-8÷(-2)-(-4)×(-3)
= -10+8÷4-12
= -10+2-12
= -20
轻装上阵走捷径
例 1 , 计算 39×
464646
787878
解: 原式= 39×
46×10101
78×10101
=39× =23
46
78
计算
1998×199919991999-1999×199819981998
原式= 1998×1999×100010001-
1999×1998×100010001
= 0
计算: (-1) +(-1) = -1+1 = 0
2001
2002
Tom Hooper started pany that provides the online tutoring& BrightSpark Education.
Early results suggest that online tutoring may improve student performance.
Exploration of Online Tutoring Test Platform in the Learning Support Services System
; https:/// online tutoring jbh124cf
BrightSpark Education says the online tutoring is used only as an addition to supplement regular teaching.
According to the existing problems, this dissertation explores the online tutoring strategies from both macro and micro perspectives.
我去喽?”七王爷也认命了,大不了过完年,讨了公告封赐,再来长期攻艰,反正那刘小医生行踪线索全无,也是要慢慢儿的磨寻——“我跟你去。”蝶宵华道。“哎?!”“我也想看看,苏明远为奴家,可以做到