a, 165:11.999 + 85.999 = (15.11):11.999 + 85.999 = [(15.11):11].999 + 85.999

= 15.(11:11).999 + 85.999 = 15.999 + 85.999 = (15+85).999 = 99900

b, 25.4 + 25:5 – 4.(30 – 5) – 5 = 25.4 + 25:5 – 4.25 – 5 = (25.4 – 4.25) + (25:5 – 5) = 0 + 0 = 0

\(a,165:11\cdot999+85\cdot999=15\cdot999+85\cdot999=999\left(15+85\right)=999\cdot100=99900\)

\(b,25\cdot4+25:5-4\left(30-5\right)-5=25\cdot4+5-4\cdot25-5=\left(25\cdot4-4\cdot25\right)+\left(5-5\right)=0+0=0\)

Cảm ơn.

= 2430 bạn nha

525 *4 + 25 / 5 - 4 * [ 30 - 5 ] - 5 + 5 * 2 = 2430

2⁴ - 30 + 5² - 4² = ( 2⁴ - 2⁴ ) - ( 30 - 5² ) = 0 - 5 = - 5

Bài 3:

a. Ta có: \(2^{30}=2^{3.10}=\left(2^3\right)^{10}=8^{10}\) 

               \(3^{20}=3^{2\cdot10}=\left(3^2\right)^{10}=9^{10}\) 

Vì 8 < 9 nên \(8^{10}< 9^{10}\) 

Vậy \(2^{30}< 3^{20}\) 

b. Ta có: \(3^{400}=3^{4.100}=\left(3^4\right)^{100}=81^{100}\) 

               \(4^{300}=4^{3.100}=\left(4^3\right)^{100}=64^{100}\) 

Vì 81 > 64 nên \(81^{100}>64^{100}\) 

Vậy \(3^{400}>4^{300}\)

a) \(18+25\times4-4^3\)

\(=18+100-64\)

\(=118-64\)

\(=54\)

b) \(275-\left(49+125\div5^3\right)\)

\(=275-\left(49+125\div125\right)\)

\(=275-\left(49+1\right)\)

\(=275-49-1\)

\(=226-1\)

\(=225\)

c) \(2015+\left(8\times15-\left(18-8\right)^2\right)\)

\(=2015+\left(8\times15-\left(10\right)^2\right)\)

\(=2015+\left(8\times15-100\right)\)

\(=2015+\left(120-100\right)\)

\(=2015+20\)

\(=2035\)

a. bằng77

b. bằng 13

lớp 2 đã học cái này rồi à

 25.5+25-25.4= 50 

hok tốt 

k mk nha mn 

=25(5+1-4)

=25x2

=50