Đặt tính rồi tính :

271 x 2= 354

372 x 4 = 1488

847 : 7 = 121

836 : 2 = 418

Đáp án:

624 : 6 = 104

Đáp án:

818  : 9  = 90 (dư 8)

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{83}\\{\,\,9}\end{array}}\\\hline{\,\,\,92}\end{array}\)                                       \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{57}\\{\,\,4}\end{array}}\\\hline{\,\,\,61}\end{array}\)

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{62}\\{\,\,8}\end{array}}\\\hline{\,\,\,70}\end{array}\)                                       \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{39}\\{\,\,5}\end{array}}\\\hline{\,\,\,44}\end{array}\)

a: =25/30+12/30=37/30

b: =24/20-15/20=9/20

c: =36/48=3/4

d: =8/17x1/6=8/102=4/51

a) \(\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)

b) \(\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)

c) \(\dfrac{36}{48}=\dfrac{3}{4}\)

d) \(\dfrac{8}{17}\times\dfrac{1}{6}=\dfrac{8}{102}=\dfrac{4}{51}\)

\(\dfrac{5}{6}+\dfrac{2}{5}=\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)

\(\dfrac{6}{5}-\dfrac{3}{4}=\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)

\(\dfrac{9}{16}\times\dfrac{4}{3}=\dfrac{36}{48}\)

\(\dfrac{8}{17}:6=\dfrac{8}{102}\)

a, 215 x 5

b, 246 x  24

c, 42 580 : 5

d, 5 719 : 34

7/5+4/5   7/20-1/4         5/4x3/9      7/2 : 8

=7+4/5    =7/20-5/20      =5/4x1/3    =7/2x 1/8

=11/5       =7-5/20          =5/12         =7/16

                 = 1/10 

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