Đặt Tính rồi tính

1256 chia 2

42 chia 78

125 chia 25

(5 + 6 + 11 - 41) x (1 + 2 + 3 + ... + 100)

= [(5 + 6)  - (11 - 41)] x (1 + 2 +...+ 100)

= [11 - 30 ] x (1 + 2 + ... + 100)

= - 19 x (1 + 2 +...+ 100)

Lớp 5 chưa học số âm.

        12 x 85 + 35 - 182 - 35 x 94

    =  1020 - 35 x (94 - 1) - 182

   = 1020 - 35 x 93 - 182

  = 1020 - 3255 - 182

  = - 2235 - 182

= - 2417

Lớp 5 chưa học số âm 

   2 x 31 x 12 + 4 x 6 + 42 + 8 x 27 x 3

= 24 x 31 + 24 + 42 + 24 x 27

= 24 x (31 + 1 + 27) + 42

= 24 x 59 + 42

= 1458

cả 2 đều là số là số 0 

a) \(9\cdot2^3-72:2^2\)

\(=72-18=54\)

b) \(125\cdot26+5^3\cdot32+25\cdot42\cdot5\)

\(=125\cdot26+125\cdot32+125\cdot42\)

\(=125\cdot\left(26+32+42\right)=125\cdot100=12500\)

c) \(5871:\left[928-\left(247-82\right)\cdot5\right]+2012^0\)

\(=5871:\left[928-\left(247-82\right)\cdot5\right]+1\)

\(=5871:\left(928-165\cdot5\right)+1\)

\(=5871:103+1\)

\(=58\)

d) \(2012+78+\left(-178\right)+\left(-2012\right)\)

\(=\left[2012+\left(-2012\right)\right]+\left[78+\left(-178\right)\right]\)

\(=-100\)

a, \(9.2^3-\frac{72}{2^2}=9.8-\frac{72}{4}=72-18=54\)

b, \(125.26+5^3.32+25.42.5\)

\(=125.26+125.32+125.42\)

\(=125.\left(26+32+42\right)\)

\(=125.100\)

\(=12500\)

c, \(\frac{5871}{\left[928-\left(247-82\right).5\right]}+2012^0\)

\(=\frac{5871}{103}+1\)

\(=57+1\)

\(=58\)

d, \(2012+78+\left(-178\right)+\left(-2012\right)\)

\(=\left[2012+\left(-2012\right)\right]+\left[78+\left(-178\right)\right]\)

\(=0+100\)

\(=100\)

sửa câu d, mình nhìn nhầm đề.

\(2012+78+\left(-178\right)+\left(-2012\right)\)

\(=\left[2012+\left(-2012\right)\right]+\left[78+\left(-178\right)\right]\)

\(=0+\left(-100\right)\)

\(=-100\)

\(\text{2045−(26+2019−56) }\)

\(\text{2045−(2045−56) }\)

\(\text{2045−1989 }\)

\(\text{56 }\)

\(\text{25.(78 - 125) - 125.(78 - 25)}\)

\(\text{25.−47−125.53 }\)

\(\text{25.−172.53}\)

thiếu phần b nha

Trả lời:

\(a,\)\(\left(2019+26\right)-\left[26+\left(2019-56\right)\right]\)

\(=2019+26-26-2019+56\)

\(=\left(2019-2019\right)+\left(26-26\right)+56\)

\(=56\)

\(b,\)\(\left(-8\right)\left(-5\right).125.\left(-13\right).20\)

\(=[\left(-8\right).125].\left[20.\left(-5\right)\right].\left(-13\right)\)

\(=(-1000).\left(-100\right).\left(-13\right)\)

\(=-1300000\)

\(c,\)\(25\left(78-125\right)-125\left(78-25\right)\)

\(=25.78-25.125-125.78+125.25\)

\(=\left(125.25-125.25\right)+78\left(25-125\right)\)

\(=0+78.\left(-100\right)\)

\(=-7800\)

Hok tốt!

Good girl

Tính

          \(\frac{15}{25}+\frac{80}{125}+\frac{12}{42}+\frac{78}{100}+\frac{18}{12}\)

          \(\frac{3}{5}+\frac{16}{25}+\frac{6}{21}+\frac{39}{50}+\frac{3}{2}\)

          \(\frac{15}{25}+\frac{16}{25}+\frac{39}{50}+\frac{6}{21}+\frac{3}{2}\)

           \(\frac{62}{50}+\frac{39}{50}+\frac{12}{42}+\frac{63}{42}\)

           \(\frac{101}{50}+\frac{75}{42}\)

           \(\frac{4242}{2100}+\frac{3750}{2100}\)

          \(\frac{7992}{2100}\)

a) (4+4)x(2019 +2019 +.....+2019)

= 8 x 125 x 2019

= (8 x 125) x 2019

= 1000 x 2019

= 2019000

b) ( 42+42+...+42)+(125+125+....+125)

= 42 x 125 + 58 x 125

= 125 x ( 42 + 58)

= 125 x 100

= 12500

 42+42+...+42)+(125+125+....+125)

= 42 x 125 + 58 x 125

= 125 x ( 42 + 58)

= 125 x 100

= 12500

1: 243^5=(3^5)^5=3^25

3*27^8=3*3^24=3^25=243^5

3: 3^300=27^100

2^200=4^100

mà 27>4

nên 3^300>2^200

4: 15^2=3^2*5^2

81^3*125^3=3^12*5^9

=>15^2<81^3*125^3

6: 125^5=5^15

25^7=5^14

mà 15>14

nên 125^5>25^7

1: 243^5=(3^5)^5=3^25

3*27^8=3*(3^3)^8=3^25

=>243^5=3*27^8

6: 125^5=(5^3)^5=5^15

25^7=(5^2)^7=5^14

=>125^5>25^7(15>14)

5: 78^12-78^11=78^11(78-1)=78^11*77

78^11-78^10=78^10*77

mà 11>10

nên 78^12-78^11>78^11-78^10