a) 538 = 5.100 + 3.10 + 8.1 = 5 . 10 2 + 3 . 10 1 + 8 . 10 0 .

b) 8609 = 8.1000 + 6.100 + 9.1 = 8 . 10 3 + 6 . 10 2 + 9 . 10 0 .

c)  a b c  = a.100 + b.100 + c.l = a . 10 2 + b . 10 1 + c . 10 0

d)  a b c d  = a.1000 + b.100 + c.10 + d =  a . 10 3 + b . 10 2 + c . 10 1 + d . 10 0

a) 126 = 1 . 10 2 + 2 . 10 1 + 6 . 10 0

b) 1068 =  1 . 10 3 + 6 . 10 1 + 8 . 10 0

c,  a 0 b =  a . 10 2 + b . 10 0

d,  a 0 b c =  a . 10 3 + b . 10 1 + c . 10 0

1.
a) \(3^4\times3^5\times3^6=3^{4+5+6}=3^{15}\)

b) \(5^2\times5^4\times5^5\times25=5^2\times5^4\times5^5\times5^2=5^{2+4+5+2}=5^{13}\)

c) \(10^8\div10^3=10^{8-3}=10^5\)

d) \(a^7\div a^2=a^{7-2}=a^5\)

2.

\(987=900+80+7\\ =9\times100+8\times10+7\\ =9\times10^2+8\times10^1+7\times10^0\)

\(2021=2000+20+1\\ =2\times1000+2\times10+1\times1\\ =2\times10^3+2\times10^1+1\times10^0\)

\(abcde=a\times10000+b\times1000+c\times100+d\times10+e\times1\\ =a\times10^4+b\times10^3+c\times10^2+d\times10^1+e\times10^0\)

còn bài 2

a)  538 = 5 . 100 + 3 . 10 + 8 . 1 = 5 . 10 2 + 3 . 10 1 + 8 . 10 0 .

b)  8609 = 8 . 1000 + 6 . 100 + 9 . 1 = 8 . 10 3 + 6 . 10 2 + 9 . 10 0 .

a)  a . 10 2 + b . 10 0

b)  a . 10 3 + b . 10 1 + c . 10 0

a)  1 . 10 2 + 2 . 10 1 + 6 . 10 0

b)  1 . 10 4 + 6 . 10 2 + 8 . 10 0

\(1024=2^{10}\)

a: \(=10^{-1}\)

b: \(=10^{-2}\)