A - B = (a - 135) - (a - 153) = 153 - 135 = 18
Vì A - B = 18 > 0, nên A > B.
Vậy, A lớn hơn B.

a.

$42(-45)-55(-42)=42(-45)+55.42=42(-45+55)=42.10=420$

b.

$(-2-3)^2-(-2)^8:(-2)^5=(-5)^2-(-2)^3=25-(-8)=33$
c.

$=\frac{1}{5}+\frac{3}{10}+\frac{3}{2}+\frac{4}{7}$

$=\frac{2}{10}+\frac{3}{10}+\frac{3}{2}+\frac{4}{7}$

$=\frac{5}{10}+\frac{3}{2}+\frac{4}{7}$
$=\frac{1}{2}+\frac{3}{2}+\frac{4}{7}=2+\frac{4}{7}=\frac{18}{7}$

d.

$=\frac{3}{22}-\frac{7}{15}-\frac{3}{22}+\frac{7}{15}-\frac{1}{2}$

$=(\frac{3}{22}-\frac{3}{22})+(\frac{-7}{15}+\frac{7}{15})-\frac{1}{2}$

$=0+0-\frac{1}{2}=\frac{-1}{2}$

e.

$=\frac{77}{12}: \frac{11}{4}+\frac{45}{4}.\frac{2}{15}$

$=\frac{7}{3}+\frac{3}{2}=\frac{23}{6}$

f.

$=\frac{-7}{11}(\frac{11}{19}+\frac{12}{19}-\frac{4}{19})$

$=\frac{-7}{11}.\frac{19}{19}=\frac{-7}{11}$
 

Số dầu ở thùng thứ nhất sẽ là:
$56 \times \frac{3}{8} = 21 \text{ lít}$
Đáp số: 21 lít dầu.

Lời giải:

$11\frac{3}{13}-(2\frac{4}{7}+5\frac{3}{13})=11\frac{3}{13}-5\frac{3}{13}-2\frac{4}{7}$

$=6-2\frac{4}{7}=4-\frac{4}{7}=\frac{24}{7}$

b) 146/13 - ( 18/7 + 68/13)

 = 146/13 - 710/91

 = 24/7 :))

a: \(42\cdot\left(-45\right)-55\cdot\left(-42\right)\)

\(=-42\cdot45+55\cdot42\)

\(=42\left(55-45\right)=42\cdot10=420\)

b: \(\left(-2-3\right)^2-\left(-2\right)^8:\left(-2\right)^5\)

\(=\left(-5\right)^2-\left(-2\right)^3\)

\(=25-\left(-8\right)=33\)

c: \(\dfrac{1}{5}-\dfrac{-3}{2}+\dfrac{4}{7}-\dfrac{3}{-10}\)

\(=\dfrac{1}{5}+\dfrac{3}{2}+\dfrac{3}{10}+\dfrac{4}{7}\)

\(=\dfrac{2+15+3}{10}+\dfrac{4}{7}=2+\dfrac{4}{7}=\dfrac{18}{7}\)

d: \(\dfrac{3}{22}-\left(\dfrac{7}{15}-\dfrac{-3}{22}\right)+\dfrac{7}{15}-\dfrac{1}{2}\)

\(=\dfrac{3}{22}-\dfrac{7}{15}+\dfrac{3}{22}+\dfrac{7}{15}-\dfrac{1}{2}\)

\(=\dfrac{3}{11}-\dfrac{1}{2}=\dfrac{-5}{22}\)

e: \(6\dfrac{5}{12}:2\dfrac{3}{4}+11\dfrac{1}{4}\cdot\left(\dfrac{1}{3}-\dfrac{1}{5}\right)\)

\(=\dfrac{77}{12}:\dfrac{11}{4}+\dfrac{45}{4}\cdot\dfrac{2}{15}\)

\(=\dfrac{77}{12}\cdot\dfrac{4}{11}+\dfrac{45}{15}\cdot\dfrac{2}{4}\)

\(=\dfrac{7}{3}+\dfrac{3}{2}=\dfrac{23}{6}\)

f: \(\dfrac{-7}{11}\cdot\dfrac{11}{19}+\dfrac{-7}{11}\cdot\dfrac{12}{19}-\dfrac{4}{19}\cdot\dfrac{-7}{11}\)

\(=\dfrac{-7}{11}\left(\dfrac{11}{19}+\dfrac{12}{19}-\dfrac{4}{19}\right)\)

\(=\dfrac{-7}{11}\cdot1=-\dfrac{7}{11}\)

C = \(\dfrac{2}{3.5}\) + \(\dfrac{2}{5.7}\) + ... + \(\dfrac{2}{99.101}\)

C = \(\dfrac{1}{3}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{1}{7}\) + ... + \(\dfrac{1}{99}\) - \(\dfrac{1}{101}\)

C = \(\dfrac{1}{3}\) - \(\dfrac{1}{101}\)

C = \(\dfrac{98}{303}\)

1 My father usually goes to work by car

2 How much does this hat cost?

3 What about singing an English song?

4 This is the oldes house in the village

5 The toy store is to the left of the book store

6 Badminon is Mai's favorite sport

7 We should plant more trees on the planet

8 How often do you go to the museum?

9 It will be sunny in the north tomorrow

10 Because she was late, she couldn't meet her music ido

Thời gian ô tô di chuyển từ A đến B ( không tính thời gian đổ xăng ) là:

     9 giờ - 7 giờ 30 phút - 10 phút = 1 giờ 20 phút

          Đáp số: 1 giờ 20 phút