早教吧作业答案频道 -->其他-->
用简便方法计算.(1)72+186+214(2)7825+9+341(3)804+1789(4)1997+5803+5003+197(5)158+36+42+264(6)386+69+214+531(7)11+14+17+…+68(8)2+6+10+…+62(9)199999+19999+1999+199+19.
题目详情
用简便方法计算. (1)72+186+214 | (2)7825+9+341 | (3)804+1789 |
(4)1997+5803+5003+197 | (5)158+36+42+264 | (6)386+69+214+531 |
(7)11+14+17+…+68 | (8)2+6+10+…+62 | (9)199999+19999+1999+199+19. |
▼优质解答
答案和解析
(1)72+186+214,
=72+(186+214),
=72+400,
=472;
(2)7825+9+341,
=7825+(9+341),
=7825+350,
=8175;
(3)804+1789,
=800+1789+4,
=2593;
(4)1997+5803+5003+197,
=(1997+5003)+(5803+197),
=7000+6000,
=13000;
(5)158+36+42+264,
=(158+42)+(36+264),
=200+300,
=500;
(6)386+69+214+531,
=(386+214)+(69+531),
=600+600,
=1200;
(7)11+14+17+…+68,
=[(11+68)×20]÷2,
=[79×20]÷2,
=790;
(9)199999+19999+1999+199+19,
=200000+20000+2000+200+20-4,
=222216.
=72+(186+214),
=72+400,
=472;
(2)7825+9+341,
=7825+(9+341),
=7825+350,
=8175;
(3)804+1789,
=800+1789+4,
=2593;
(4)1997+5803+5003+197,
=(1997+5003)+(5803+197),
=7000+6000,
=13000;
(5)158+36+42+264,
=(158+42)+(36+264),
=200+300,
=500;
(6)386+69+214+531,
=(386+214)+(69+531),
=600+600,
=1200;
(7)11+14+17+…+68,
=[(11+68)×20]÷2,
=[79×20]÷2,
=790;
(9)199999+19999+1999+199+19,
=200000+20000+2000+200+20-4,
=222216.
看了 用简便方法计算.(1)72+...的网友还看了以下:
2000减197 用简便算法怎么做 2020-05-13 …
一桶油,第一次用去2/3千克,第二次用去1/5千克,第三次用去前两次总重的1/4,第三次用去多少千 2020-05-14 …
两个等差数列:2,5,8,…,197和2,7,12,…,197中,(1)有多少个相同的项;(2)求 2020-07-11 …
203×197用简便方法计算 2020-07-18 …
1200-197用简便算法算 2020-07-18 …
1*100+3*99+5*98+.+197*2+199*1=? 2020-07-18 …
200×199-199×198+198×197-197×196+…+2×1=. 2020-07-18 …
1,3.6*42.3*3.75-12.5*0.423*282,1.001+2.003+1.005+ 2020-07-19 …
(应用题)一桶油12升,第一次用去1/4,第二次用去了1/4升,剩多少没用完?如第三天又用去整桶一桶 2020-11-24 …
急用关于文章层次序号用11.11.1.1……时的详细用法当文章层次序号用11.11.1.11.1.1 2020-12-12 …