Question

[Hồng Hạnh]

thực hiện phép tính một cách hợp lí :

123.456+123.789+1245.23

\(2^9:16^2+81^5:3^{18}-125^7:625^5\)

Answer 1

[Bui Danh]

a)Ta có\(123\times456+123\times789+1245\times23\)

           \(=123\left(456+789\right)+1245.23\)

           \(=123.1245+1245.23\)

            \(=1245\left(123+23\right)\)

             \(=1245.146\)

              \(=181770\)

b)\(2^9:16^2+81^5:3^{18}-125^7:625^5\)

\(=2^9:\left(2^4\right)^2+\left(3^4\right)^5:3^{18}-\left(5^3\right)^7:\left(5^4\right)^5\)

\(=2^9:2^8+3^{20}:3^{18}-5^{21}:5^{20}\)

\(=2+3^2-5\)

\(=2+9-5\)

\(=6\)