\(1235\text{×}6789\text{×}\left(630-315\text{×}2\right)\)

\(=1235\text{×}6789\text{×}\left(630-630\right)\)

\(=1235\text{×}6789\text{×}0=0\)

\(\left(100+67\right)\text{×}67+\left(200-38\right)\text{×}33\)

\(=167\text{×}67+167\text{×}33\)

\(=167\text{×}\left(67+33\right)\)

\(=167\text{×}100=16700\)

\(72+36\text{×}2+24\text{×}3+18\text{×}4+12\text{×}2+168\)

\(=72+72+72+72+24+168\)

\(=\left(72\text{×}4\right)+24+168=288+24+168=480\)

a) \(1235\times6789\times\left(630-630\right)\)

\(=1235\times6789\times0\)

\(=1235\times0\)

\(=0\)

b) \(167\times67+167\times33\)

\(=167\times\left(67+33\right)\)

\(=167\times100\)

=16700

Ta có :

\(A=\frac{1}{3}-\frac{3}{4}-\left(-\frac{3}{5}\right)+\frac{1}{72}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)

\(\Rightarrow A=\frac{5}{15}-\frac{54}{72}+\frac{9}{15}+\frac{1}{72}-\frac{16}{72}-\frac{1}{72}+\frac{1}{15}\)

\(\Rightarrow A=\left(\frac{5}{15}+\frac{9}{15}+\frac{1}{15}\right)+\left(-\frac{54}{72}+\frac{1}{72}-\frac{16}{72}-\frac{2}{72}\right)\)

\(\Rightarrow A=1-\frac{71}{72}=\frac{1}{72}\)

 345,25 : 0,125 + 345,25 : 0,25 + 345,25 :1/2

= 345,25 : 0,125 + 345,25 : 0,25 + 345,25 :1/2

=345,25x8+345,25x4+345,25x0,5

=345,25x(8+4+0,5)

=345,25x12.5

=4315.625

36 x 5 + 72 x 2 - 216 + 144

= 252

\(36\text{×}5+72\text{×}2-216+144\)

\(=36\text{×}5+36\text{×}2\text{×}2-36\text{×}6+36\text{×}4\)

\(=36\text{×}5+36\text{×}4-36\text{×}6+36\text{×}4\)

\(=36\text{×}\left(5+4-6+4\right)=36\text{×}7=252\)

6,28 : 0,25 + 6,28 x 6

= 6,28 x 4 + 6,28 x 6

= 6,28 x ( 4 + 6 )

= 6,28 x 10

= 62,8

6,28 : 0,25 + 6,28 x 6

= 6,28 x 4 + 6,28 x 6

= 6,28 x ( 4 + 6 )

= 6,28 x 10

= 62,8

k mk nha 

Mk cảm ơn bạn nhiều

Thank you very much

( ^ _ ^ )

6,28.(0,25+6)

=6,28.6,25

=39,25

Tính thuận tiện :

2x 4 x 8 x 0,5 x 0,125 x 0,25 x ( 0,4321 + 0,5679 )

= 2 x 4 x 8 x 0,5 x 0,125 x 0,25 x 1

= ( 2 x 0,5 ) x ( 4 x 0,25 ) x ( 8 x 0,125 ) x 1

=    1x1x1x1

= 1

Tính nhanh :

72,9 x 99 + 72 + 0,9

= 72,9 x 99 + 72,9

= 72,9 x 99 + 72,9 x 1

= 72,9 x ( 100 x 1 )

= 72,9 x 100

= 7290

Câu 1: 

2 * 4 * 8 *0,5 * 0,125 * 0,25 * (0,4321 + 0,5679)

= (0,5 * 2) * (4 * 0,25) * (8 * 0,125) * 1

=    1    *     1          *           1          * 1 = 1

Câu 2:

72,9 * 99 + 72 + 0,9

= 72,9 * 99 + 72,9

=  72,9 * (99 + 1)

= 72,9 * 100

=     7290

2×4×8×0,5×0,125×0,25 +(0,4321+0,5679)=(2×0,5)×(4×0,25)×(0,125×8)+1=1×1×1+1=2

72,9×99+72+0,9=72,9×99+72,9=72,9×(99+1)=72,9×100=7290

120+[1+2+3...+9+100]x[4x9-36]

=120+1+2+3...+9+100]x0

=120+0

=120

bằng 120 nhé

dễ mak bn ơi

\(=\dfrac{45\cdot100\cdot0.25}{35\cdot100\cdot36}=\dfrac{45}{36}\cdot\dfrac{0.25}{35}=\dfrac{5}{4}\cdot\dfrac{1}{140}=\dfrac{1}{28\cdot4}=\dfrac{1}{112}\)

1/112

mn giải rõ giúp mik nha

\(13,25:0,5+13,25:0,25+13,25:0,125\)

\(=13,25:\left(0,5+0,25+0,125\right)\)

\(=13,25:0,875\)

\(\approx15,15\)

   13,25:0,5+13,25:0,25+13,25+0,125

=13,25:(0,5+0,25+0,125)

=13,25:0,875

=15,1428571

13,25:0,5+13,25:0,25+13,25:0,125

=13,25x2+13,25x4+13,25x8

=13,25x(2+4+8)

=13,25x14

=185,5