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b, 3/5 + 4/7 + 2/8 + 10/25 + 9/21 + 28/16
= 3/5 + 4/7 + 2/8 + 2/5 + 3/7 + 14/8
= (3/5 + 2/5) + ( 4/7 + 3/7) + ( 2/8 + 14/8)
= 1 + 1 + 7/4
= 2 + 7/4 = 15/4
c , 8/7 + 7/6 + 5/8 + 10/12 + 24/28 + 6/16
= c , 8/7 + 7/6 + 5/8 + 5/6 + 6/7 + 1/2
= (8/7 + 6/7) + (7/6 + 5/6) + 5/8 + 1/2
= 14/7 + 12/6 + 5/8 + 1/2
= 2 + 2 + 5/8 + 1/2
= 4 + 9/8 = 41/8
a)25/50 + 5/15 = 1/2 + 1/3 = 5/6
b)72/90 + 7/28 = 4/5 + 1/4 =\(1\frac{1}{20}\)
c)32/96 + 8/28 = 1/3 + 2/7 = 13/21
Chúc bạn tết vui vẻ nha!
\(\frac{25}{50}+\frac{5}{15}=\frac{1}{2}+\frac{1}{3}=\frac{3}{6}+\frac{2}{6}=\frac{5}{6}\)
\(\frac{72}{90}+\frac{7}{28}=\frac{8}{10}+\frac{1}{4}=\frac{32}{40}+\frac{10}{40}=\frac{42}{40}=\frac{21}{20}\)
\(\frac{32}{96}+\frac{8}{28}=\frac{1}{3}+\frac{2}{7}=\frac{7}{21}+\frac{6}{21}=\frac{13}{21}\)
a, \(\frac{25}{50}\)= \(\frac{25:25}{50:25}\)= \(\frac{1}{2}\) \(\frac{5}{15}\)= \(\frac{5:5}{15:5}\)= \(\frac{1}{3}\)
\(\frac{1}{2}\)+ \(\frac{1}{3}\)= \(\frac{3}{6}\)+ \(\frac{2}{6}\)= \(\frac{5}{6}\)
b, \(\frac{72}{90}\)= \(\frac{72:18}{90:18}\)= \(\frac{4}{5}\) \(\frac{7}{28}\)= \(\frac{7:7}{28:7}\)= \(\frac{1}{4}\)
\(\frac{4}{5}\)+ \(\frac{1}{4}\) = \(\frac{16}{20}\)+ \(\frac{5}{20}\)= \(\frac{21}{20}\)
c, \(\frac{32}{96}\)= \(\frac{32:32}{96:32}\)= \(\frac{1}{3}\) \(\frac{8}{28}\)= \(\frac{8:4}{28:4}\)= \(\frac{2}{7}\)
\(\frac{1}{3}\)+ \(\frac{2}{7}\) = \(\frac{7}{21}\)+ \(\frac{6}{21}\)= \(\frac{13}{21}\)
Lời giải và hướng dẫn:
a) 25/50 + 5/15 = 1/2 + 1/3 = 3/6 + 2/6 = 5/6.
b) 72/90 + 7/28 = 4/5 + 1/4 = 16/20 + 5/20 = 21/20.
c) 32/96 + 8/28 = 1/3 + 2/7 = 7/21 + 6/21 = 13/21.
A)\(\frac{25}{50}+\frac{5}{15}\)
\(=\frac{1}{2}+\frac{1}{3}\)
\(=\frac{3+2}{6}\)\(=\frac{5}{6}\)
B) \(\frac{72}{90}+\frac{7}{28}\)\(=\frac{4}{5}+\frac{1}{4}\)\(=\frac{16+5}{20}\)\(=\frac{21}{20}\)
C)\(\frac{32}{96}+\frac{8}{28}\)\(=\frac{1}{3}+\frac{2}{7}\)\(=\frac{7+6}{21}\)=\(\frac{13}{21}\)
NĂM MỚI VUI VẺ
a) 2/5+9/5=11/5
b) 15/45+25/30=7/6
c) 28/32+45/72=3/2
d) 8/28+5/30=19/42
bài 2
a) x - 4/5 =4/5 + (3/7+3/5)
x-4/5=4/5+36/35
x-4/5=64/35
x=64/35+4/5
x=92/35
b) x-7/35=4/5
x=4/5+7/35
x=1
nhớ tk m nhé
a = 18/5
b = 3/9 + 5/6 = 6/18 + 25/18 = 31/18
c = 7/8 + 5/8 = 12/8
d = 4/14 + 1/6 = 14/42 + 7/42 = 21/42 -= 7/14
b2
x - 4/5 = 4.5 + ( 3/7 + 3/5 )
x - 4/5 = 49/35
x = 49/35 + 4/5
x = 77/35
x - 7/35 = 4/5
x = 4/5 + 7/35
x = 1
mình ko chắc chắn đâu
mình nghĩ mình làm sai
a) 1+2+3+4+5+6+7+8+9
= (1+9)+(2+8)+(3+7)+(4+6)+5
= 10+10+10+10=5
= 45
b) 19+28+37+46+81+72+63+54
= (19+81)+(28+72)+(46+54)+(63+37)
= 100+100+100+100
= 400
a]27/45+25/15=3/5+5/3=34/15
b]28/32+45/72=7/8+5/8=12/8=3/2
c]8/28+5/30=2/7+1/6=19/42
a. ….= 50 : 10 = 5
Hoặc…= 50 : 2 : 5 = 25 : 5 = 5
Hoặc…= 50 : 5 : 2 = 10 : 2 = 5
b. Kết quả: 1
c. Kết quả: 2
Câu 1:Tính hợp lí
a) 28.72+28.28
=28.(72+28)
=28.100
= 2800
b)50.5.2
=50.2.5
=100.5
= 500
Câu 2:Tìm x
a) 3x+6=15
3x =15-6
3x = 9
x = 9:3
x = 3
b)100-(4x+8):10=8
100-(4x+8) =8.10
100-(4x+8) = 80
4x+8 = 100-80
4x+8 = 20
4x = 20-8
4x = 12
x = 12:4
x = 3
K cho mk nhé!!!!!Thanks>_<
câu 1
a )
28x72+28x28
=28+72
=100
b )
50x5x2
=50x10
=500
câu 2
a )
3x+6=15
3x=15-6
3x=9
x=9:3
x=3
b)
100-(4x+8):10=8
100-(4x+8=)8x10
100-(4x+8)=80
4x+8=100-80
4x+8=20
4x=20-8
4x=12
x=12:4
x=3