Question

Bài 1: Tính bằng cách hợp lí: 

a, \(11\frac{1}{4}-\left(2\frac{5}{7}+5\frac{1}{4}\right)\)

b, \(\left(8\frac{5}{11}+3\frac{5}{8}\right)-3\frac{5}{11}\)

c, \(-\frac{1}{4}.13\frac{9}{11}-0,25.6\frac{2}{11}\)

d, \(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)

Bài 2: Tính bằng cách hợp lí( nếu có)

a,\(\left(1,11+0,19-26\right):\left(2,06+0,54\right)-\left(\frac{1}{2}+\frac{1}{3}\right):2\)

b, \(\left(2\frac{1}{3}+3,5\right):\left(-4\frac{1}{6}+3\frac{1}{7}\right)+7,5\)

c, \(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8\)

Bài 3: Tìm x, biết:

a, \(\frac{2}{7}+x=20,75\)

b, \(-4\frac{1}{5}-x=2,25\)

c, \(x:8,5=2,2\)

d, \(\left(\frac{2x}{5}-1\right):\left(-5\right)=\frac{1}{7}\)

Answer 1

a) 11 1/4- 2 5/7 - 5 1/4

11 1/4 - 5 1/4 - 2 5/7

( 11 -5) + ( 1/4 -1/4) -2 5/7

6 +0 -2 5/7

6- 2 5/7

5+1 - 2 5/7

( 5-2) + ( 1-5/7)

3+( 7/7 -5/7)

3 + 2/7

3 2/7

3+