早教吧作业答案频道 -->数学-->
小数运算的速算和简算,1.2121212÷3.303033.3+3.33+3.333+3.3333+3.333331990×198.9-1989×198.860.7×0.60.45×172-0.9×71×0.5-0.45简算不是直接计算,这样我老早就直接用计算机算了
题目详情
小数运算的速算和简算,
1.2121212÷3.30303
3.3+3.33+3.333+3.3333+3.33333
1990×198.9-1989×198.8
60.7×0.6
0.45×172-0.9×71×0.5-0.45
简算不是直接计算,这样我老早就直接用计算机算了
1.2121212÷3.30303
3.3+3.33+3.333+3.3333+3.33333
1990×198.9-1989×198.8
60.7×0.6
0.45×172-0.9×71×0.5-0.45
简算不是直接计算,这样我老早就直接用计算机算了
▼优质解答
答案和解析
1.2121212÷3.030303(怀疑此题抄丢一个零,故加上一个零)
=1.2*1.010101/3*1.010101
=0.4
3.3+3.33+3.333+3.3333+3.33333
=3*1.1+3*1.11+3*1.111+3*1.1111+3*1.11111
=3*(1.1+1.11+1.111+1.1111+1.11111)
=3*5.5432
1990×198.9-1989×198.8
=1990×198.9-(1990×198.8-198.8)
=1990×198.9-1990×198.8+198.8
=1990×(198.9-198.8)+198.8
=1990*0.1+198.8
=199+198.8
60.7×0.6
=(60+0.7)*0.6
=36+0.42
=36.42
0.45×172-0.9×71×0.5-0.45
=0.45×172-0.45×71-0.45
=0.45*(172-71-1)
=0.45*100
=45
用键盘写算式太费劲.有的题没计算到最后,计算到最后的答案也未必对.只是方法和思路应该是正确的.时间匆匆,有不准确的地方,见谅!
=1.2*1.010101/3*1.010101
=0.4
3.3+3.33+3.333+3.3333+3.33333
=3*1.1+3*1.11+3*1.111+3*1.1111+3*1.11111
=3*(1.1+1.11+1.111+1.1111+1.11111)
=3*5.5432
1990×198.9-1989×198.8
=1990×198.9-(1990×198.8-198.8)
=1990×198.9-1990×198.8+198.8
=1990×(198.9-198.8)+198.8
=1990*0.1+198.8
=199+198.8
60.7×0.6
=(60+0.7)*0.6
=36+0.42
=36.42
0.45×172-0.9×71×0.5-0.45
=0.45×172-0.45×71-0.45
=0.45*(172-71-1)
=0.45*100
=45
用键盘写算式太费劲.有的题没计算到最后,计算到最后的答案也未必对.只是方法和思路应该是正确的.时间匆匆,有不准确的地方,见谅!
看了 小数运算的速算和简算,1.2...的网友还看了以下:
1.因为l1⊥l3,l2⊥l3,所以l1⊥l2()2.因为∠1∠2互余,所以∠1+∠2=90°() 2020-05-14 …
8年级数学题:3的n次方+m能被13整除,证明3的n+3次方能被13整除.急用,谢谢刚知道:3^( 2020-05-15 …
初一下半学期数学练习册题目P14习题12.7(2)(3的1/3次方除以2的1/2次方)的6次方第2 2020-05-23 …
帮忙已知1×2×3=6,2×3×4=24,3×4×5=60,…,试证明:对任意的整数n,所有形如n 2020-06-03 …
列竖式计算.0.45×3.06=60.3÷18=0.82×2.13≈(保留两位小数)16÷33=( 2020-06-27 …
口算60×3=79×0=810÷9=7.8+2=714÷8≈300×8=25×4=8.9-3.6= 2020-07-22 …
已知下列条件求三角形用正弦定理解1.题``A=45度```B=60度````a=102题``b=3 2020-08-02 …
口算.60÷3=44÷4=0÷7=50÷5=42÷2=66÷3=4500÷5=0÷9= 2020-10-30 …
心算60÷3=1.4-0.8=300÷6=140÷2=46+38=240÷6=1800÷9=4200 2020-10-30 …
六年级分数速算与巧算有3道题望大虾们能帮帮ME(简算!!急!!)0.375*(7/9+14/51)+ 2020-12-09 …