300

465 

2/15-2/65-4/39=4/39-4/39=0

32/13-(7/23+8/23)=32/13-15/23=541/299

(1/3+12/67+13/41) - (79/67 - 28/41)=6836/8241-1363/2747=1/3

38/145 - (8/45-17/51-3/11)=38/145-(-212/495)=1982/2871

( 12 + 68) + ( 13 + 67 ) + (14 + 66 ) + (15 + 65 ) ( 0.5 )

= 80 + 80 + 80 + 80 ( 0.5 )

= 80 x 4 = 320 ( 0.5 )

b. Tìm được số a : 16 : 2 = 8

1/4 của số a là : 8 : 4 = 2 

Đáp số: 2                      

1: =-12

2: =11

Chọn A.

Dựa vào bảng đã cho ta có bảng phân bố tần số; tần suất như sau:

Đáp án:

 a, 38+41+117+159+6238+41+117+159+62

=(38+62)+(41+159)+117=(38+62)+(41+159)+117

=100     +200      +117=100     +200      +117

=417=417

b, 73+86+968+914+303273+86+968+914+3032

=73+(86+914)+(968+3032)=73+(86+914)+(968+3032)

=73+1000     +4000=73+1000     +4000

=5073=5073

c, 341.67+341.16+659.83341.67+341.16+659.83

=341.(67+16)+659.83=341.(67+16)+659.83

=341.83+659.83=341.83+659.83

=83.(341+659)=83.(341+659)

=83.1000=83000=83.1000=83000

d, 42.53+47.156−47.11442.53+47.156-47.114

=42.53+47.(156−114)=42.53+47.(156-114)

=42.53 +47.42=42.53 +47.42

=42.(53+47)=42.100=42.(53+47)=42.100

=4200=4200

e, 563.23+23.26+23563.23+23.26+23

=23.(563+26+1)=23.(563+26+1)

=23.600=23.600

=13800=13800

f, 132+157+43+68132+157+43+68

=(132+68)+(157+43)=(132+68)+(157+43)

=200      +200=400=200      +200=400

g, 49.68+100.34+6849.68+100.34+68

=49.68+50.68+68=49.68+50.68+68

=68.(49+50+1)=68.(49+50+1)

=68.100=6800=68.100=6800

h, 491.(267+53)+491.(151+67)491.(267+53)+491.(151+67)

=491.(267+53+151+67)=491.(267+53+151+67)

=491.538=491.538

=264158=264158

Vote mk nha.

a) \(38 + 41 + 117 + 159 + 62\) \(= (38 + 62) + (41 + 159) + 117\)
\(= 100 + 200 + 117\)
\(=417\)

b) \(73 + 86 + 968 + 914 + 3032\) \(= 73 + (86 + 914) + (968 + 3032)\)
\(= 73 + 1000 + 4000\)
\(=5073\)

c) \(341 \cdot 67 + 341 \cdot 16 + 659 \cdot 83\) \(= 341 \cdot (67 + 16) + 659 \cdot 83\)
\(= 341 \cdot 83 + 659 \cdot 83\)
\(= (341 + 659) \cdot 83\)
\(= 1000 \cdot 83\)
\(=83000\)

e) \(563 \cdot 23 + 23 \cdot 36 + 23\) \(= 563 \cdot 23 + 23 \cdot 36 + 23 \cdot 1\)
\(= 23 \cdot (563 + 36 + 1)\)
\(= 23 \cdot 600\)
\(=13800\) f) \(132 + 157 + 43 + 68\) \(= (132 + 68) + (157 + 43)\)
\(= 200 + 200\)
\(=400\)

g) \(49 \cdot 68 + 100 \cdot 34 + 68\) \(= 49 \cdot 68 + 50 \cdot 68 + 1 \cdot 68\) (vì \(100 \cdot 34 = 50 \cdot 68\))
\(= (49 + 50 + 1) \cdot 68\)
\(= 100 \cdot 68\)
\(=6800\)