ythequotie
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dfivedecreasedbythesumofeighta
dfour
8、explai
howtorou
d
umbers解释如何四舍五入近似值approximatio
估算estimatio
Togivea
approximatevalue即取一个近似值。将一个整数四舍五入到所要求的位数值，若所要求位数右边的数字小于5，则将其约去，若大于或等于5，则进一位。Whe
rou
di
ga
umbertoagive
placevalueifthedigittotherightoftheo
egive
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orequaltofiveyourou
dupExamplerou
d67tothe
earestte
’splace”7”isgreatertha
“5”sorou
d“67”upto“70”
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dthe
umber5842tothe
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dredThefouri
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fivesoyourou
ddow
to5800进位carry截尾tru
catio
四舍五入rou
d下舍入rou
ddow
上舍入rou
dup有效数字sig
ifica
tdigit无效数字i
sig
ifica
tdigit
9、验算Howca
youusemultiplicatio
tochecktheresultofadivisio
problemexample4191multiplythequotie
tbythedivisor4x9362addtheremai
dertotheproductofitem1above36541二、整数
1、数数字digit；零
ullzero
ought
il数
umber；整数whole
umber，i
teger正positive；正数positive
umber；正整数positivewhole
umber负
egative（a
umberthatislesstha
zero）；负数
egative
umber；非负的
o
egative；负整数
egativewhole
umberopposite
umbers相反数；real
umbers实数
umberli
e数轴origi
原点Arithmetic算术algebra代数geometry几何ge
erated旋转average平均数
atural
umber自然数：Thesameasacou
ti
g
umberItisamemberoftheset｛0，1，2，3，4……｝ratio
al
umber有理数：A
umberthatca
bereprese
tedbyafractio
分数Thisi
cludesalltermi
ati
ga
drepeati
gdecimals整数i
teger：A
ypositiveor
egative
umberorzeroAmemberoftheset｛…3210，1，2，3，…｝整数whole
umbers：Allthe“
atural
umbers”pluszeroirratio
al
umber无理数A
o
repeati
g（无限）
o
termi
ati
g（不循环）decimal实数real
umber：A
yratio
alorirratio
al
umber连续整数co
secutive
umberCou
ti
g连续的数or
atural
umbers（自然数）The
umbersyoucou
twith123…etcEve
umbers；eve
i
teger偶数Whole
umbersdivisiblebytwo024…Odd
umbers；oddi
teger奇数Whole
umbers
otdivisiblebytwoprime
umber质数：A
umberwhichhas
ofactorsothertha
itselfor1Listallofthe
o
prime
umbers合数betwee
15a
d30prime
umber质数：A
umberwhichhasexactlytwowhole
umberfactorso
ea
ditselfprimefactor质因数Afactorofa
umberwhichisalsoaprime
umber49
410
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hasfactorsor