a,112,5:5+4=22,5+4=26,5　b.4,8+28:16=4,8+1,75=6,55　c.702:7,2-7＝97,5-7=90,5 . bn xuống dòng nha , máy tính mik ko xuống đc nên viết như vậy á . Nếu đúng cho mik xin 1 tick ạ　　　　　　　　　　　　　　　　　　　　　　　　

a, 112,5 : 5 + 4

= 22,5 + 4 = 26,5

b, 4,8 + 28 : 16

= 4,8 + 1,75 = 6,55

c, 702 : 7,2 – 7

= 97,5 – 7 = 90,5

6/11 + 17/28 + 5/11 + 24/60 + 11/28 + 3/5

= ( 6/11 + 5/11 ) + ( 17/28 + 11/28 ) + 24/60 + 3/5

= 1 + 1 + 1

= 3

6/11 + 17/28 + 5/11 + 24/60 + 11/28 + 3/5

= ( 6/11 + 5/11 ) + ( 17/28 + 11/28 ) + 24/60 + 3/5

= 1 + 1 + 1

= 3

a: \(-\frac{10}{3}+\frac{13}{10}-\frac16+\frac{7}{10}\)

\(=\left(-\frac{10}{3}-\frac16\right)+\left(\frac{13}{10}+\frac{7}{10}\right)\)

\(=-\frac{21}{6}+\frac{20}{10}=-\frac72+2=-\frac32\)

b: \(1-\frac{20}{6}+\frac{39}{30}-\frac{4}{24}+\frac{34}{50}\)

\(=1-\frac{20}{6}+\frac16+1,3+0,68\)

\(=1-\frac{19}{6}+1,98=2,98-\frac{19}{6}=\frac{298}{100}-\frac{19}{6}=\frac{-56}{300}=\frac{-14}{75}\)

c: \(\frac{15}{24}-\frac{6}{26}+\frac{28}{48}-\frac{30}{39}+\frac{10}{24}\)

\(=\left(\frac{15}{24}+\frac{10}{24}+\frac{28}{48}\right)-\left(\frac{3}{13}+\frac{10}{13}\right)\)

\(=\left(\frac{25}{24}+\frac{14}{24}\right)-1=\frac{39}{24}-1=\frac{15}{24}=\frac58\)

d: \(-\frac{5}{10}+\frac{12}{28}-\frac{3}{27}-\frac{7}{18}+\frac{20}{35}\)

\(=-\frac12+\frac37-\frac19-\frac{7}{18}+\frac47\)

\(=\left(-\frac12-\frac19-\frac{7}{18}\right)+\left(\frac37+\frac47\right)=-1+1=0\)

Học sinh nhẩm và ghi kết quả như sau:

35 : 5 = 7

28 : 7 = 4

24 : 6 = 4

21 : 3 = 7

35 : 7 = 5

28 : 4 = 7

24 : 4 = 6

21 : 7 = 3

35 : 5 = 7

28 : 7 = 4

24 : 6 = 4

21 : 3 = 7

35 : 7 = 5

28 : 4 = 7

24 : 4 = 6

21 : 7 = 3

27,5% + 38% = 65,5%

30% - 16% = 14%

216% : 8 = 27%

14,2% x 4 = 56,8%