核心提示: 简便运算:一、加法交换律:加法交换律的概念为:两个加数交换位置,和不变。字母公式:a+b+c=a+c+b =963+37-589
=963+37-589 |
963-589+37
|
=1000-589
|
=411
|
=472+228+156
|
472+156+228
|
=700+156
|
=856
|
=(58+42)+(154+246) |
58+154+246+42
|
=100+400
|
=500
|
=900-(245+355)
|
900-245-355
|
=900-600
|
=300
|
=158+(637+263)
|
(158+637)+263
|
=158+900
|
=1058
|