Câu hỏi của ✰ĖӾØ✰ Flo

Question

giúp e lm bài 8 :)

Khánh Quỳnh · Accepted Answer

`a, ( 317 + 49 ) - 117``= ( 317 - 117 ) + 49``= 200 + 49``= 249`______________________________`b, 1637 - ( 137 - 98 )``= ( 1637 - 137 ) + 98``= 1500 + 98``= 1598`___________________________________`c, 853 - ( 89 + 753 )``= ( 853 - 753 ) - 89``= 100 - 89``= 11`________________________________`d, ( 2100 - 42 ) : 21``= ( 2100 : 21 ) - ( 42 : 21 )``= 100 - 2``= 98`________________________________`e, 17 * 13 + 17 * 42 - 17 * 35``= 17 * ( 13 + 42 - 35 )``= 17 * ( 13 + 7 )``= 17 * 20``= 340`________________________________________`f, ( 76 * 35 + 76 * 19 ) : 54``= [ 76 * ( 35 + 19 ) ] : 54``= ( 76 * 54 ) : 54``= 76 * ( 54 : 54 )``= 76 * 1``= 76`_______________________________________________`g, 53 * 39 + 47 * 39 - 53 * 21 - 47 * 21``= 53 * ( 39 - 21 ) + 47 * ( 39 - 21 )``= 53 * 18 + 47 * 18``= ( 53 + 47 ) * 18``= 100 * 18``= 1800`___________________________________________________`h, ( 252 + 2 * 28 - 5 * 28 ) : 28``= ( 9 * 28 + 2 * 28 - 5 * 28 ) : 28``= [( 9 + 2 - 5 ) * 28 ] : 28``= ( 9 + 2 - 5 ) * ( 28 : 28 )``= ( 11 - 5 ) * 1``= 6 * 1``= 6`___________________________________________________`i)2.53.12+4.6.87-3.8.40``=(2.12).53+(4.6).87-(3.8).40``=24.53+24.87-24.40``=24.(53+87-40)``=24.100``=2400`___________________________________________________`k)5.7.77-7.60+49.25-15.42``=(5.7).77-7.5.12+7.7.5.5-3.5.7.6``=35.77-(7.5).12+(7.5).7.5-(5.7).3.6``=35.77-35.12+35.35-35.18``=35.(77-12+35-18)``=35.82``=2870`Câu trả lời: `a, ( 317 + 49 ) - 117``= ( 317 - 117 ) + 49``= 200 + 49``= 249`______________________________`b, 1637 - ( 137 - 98 )``= ( 1637 - 137 ) + 98``= 1500 + 98``= 1598`___________________________________`c, 853 - ( 89 + 753 )``= ( 853 - 753 ) - 89``= 100 - 89``= 11`________________________________`d, ( 2100 - 42 ) : 21``= ( 2100 : 21 ) - ( 42 : 21 )``= 100 - 2``= 98`________________________________`e, 17 * 13 + 17 * 42 - 17 * 35``= 17 * ( 13 + 42 - 35 )``= 17 * ( 13 + 7 )``= 17 * 20``= 340`________________________________________`f, ( 76 * 35 + 76 * 19 ) : 54``= [ 76 * ( 35 + 19 ) ] : 54``= ( 76 * 54 ) : 54``= 76 * ( 54 : 54 )``= 76 * 1``= 76`_______________________________________________`g, 53 * 39 + 47 * 39 - 53 * 21 - 47 * 21``= 53 * ( 39 - 21 ) + 47 * ( 39 - 21 )``= 53 * 18 + 47 * 18``= ( 53 + 47 ) * 18``= 100 * 18``= 1800`___________________________________________________`h, ( 252 + 2 * 28 - 5 * 28 ) : 28``= ( 9 * 28 + 2 * 28 - 5 * 28 ) : 28``= [( 9 + 2 - 5 ) * 28 ] : 28``= ( 9 + 2 - 5 ) * ( 28 : 28 )``= ( 11 - 5 ) * 1``= 6 * 1``= 6`___________________________________________________`i)2.53.12+4.6.87-3.8.40``=(2.12).53+(4.6).87-(3.8).40``=24.53+24.87-24.40``=24.(53+87-40)``=24.100``=2400`___________________________________________________`k)5.7.77-7.60+49.25-15.42``=(5.7).77-7.5.12+7.7.5.5-3.5.7.6``=35.77-(7.5).12+(7.5).7.5-(5.7).3.6``=35.77-35.12+35.35-35.18``=35.(77-12+35-18)``=35.82``=2870`

Bảo Chu Văn An · Answer

a) $\left(317+49\right)-117=\left(317-117\right)+49=200+49=249$b) $1637-\left(137-98\right)=\left(1637-137\right)-98=1500-98=1402$c) $853-\left(89+753\right)=89+\left(853-753\right)=89+100=189$d) $\left(2100-42\right)
:
21=2100
:
21-42=100-42=58$e) $17
.
13+17
.
42-17
.
35=17
.
\left(13+42-35\right)=17
.
20=340$f) $\left(76
.
35+76
.
19\right)
:
54=76
.
\left(35+19\right)
:
54=76
.
54
:
54=76
.
1=76$g) $53
.
39+47
.
39-53
.
21-47
.
21=\left[\left(53+47\right)
.
39\right]-\left[\left(53+47\right)
.
21\right]=100
.
39-100
.
21=100
.
\left(39-21\right)=100
.
18=1800$i) $2
.
53
.
12+4
.
6
.
87-3
.
8
.
40=2
.
12+4
.
6-3
.
8
.
\left(53+87-40\right)=24+24-24
.
100=24
.
100=2400$k) $5
.
7
.
77-7
.
60+49
.
25-15
.
42=5
.
7
.
11
.
7-7
.
60+7
.
7
.
5
.
5-15
.
6
.
7=7
.
\left(385-60+175-90\right)=7
.
410=2870$Câu trả lời: a) $\left(317+49\right)-117=\left(317-117\right)+49=200+49=249$b) $1637-\left(137-98\right)=\left(1637-137\right)-98=1500-98=1402$c) $853-\left(89+753\right)=89+\left(853-753\right)=89+100=189$d) $\left(2100-42\right)
:
21=2100
:
21-42=100-42=58$e) $17
.
13+17
.
42-17
.
35=17
.
\left(13+42-35\right)=17
.
20=340$f) $\left(76
.
35+76
.
19\right)
:
54=76
.
\left(35+19\right)
:
54=76
.
54
:
54=76
.
1=76$g) $53
.
39+47
.
39-53
.
21-47
.
21=\left[\left(53+47\right)
.
39\right]-\left[\left(53+47\right)
.
21\right]=100
.
39-100
.
21=100
.
\left(39-21\right)=100
.
18=1800$i) $2
.
53
.
12+4
.
6
.
87-3
.
8
.
40=2
.
12+4
.
6-3
.
8
.
\left(53+87-40\right)=24+24-24
.
100=24
.
100=2400$k) $5
.
7
.
77-7
.
60+49
.
25-15
.
42=5
.
7
.
11
.
7-7
.
60+7
.
7
.
5
.
5-15
.
6
.
7=7
.
\left(385-60+175-90\right)=7
.
410=2870$

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