Question

tính hợp lí:

a) 5.11.18+9.31.10+4.29.45

b) 37.39+78.14+13.85+52.55

Answer 1

a: =90(11+31+29*2)

=90*100=9000

b: =13(37*3+6*14+85+4*55)

=13*500=6500

Answer 2

a) \(5.11.18+9.31.10+4.29.45\)

\(=\left(18.5\right).11+\left(9.10\right).31+\left(45.4\right).29\)

\(=90.11+90.31+90.2.29\)

\(=90.\left(11+31+2.29\right)\)

\(=90.\left(11+31+58\right)\)

\(=90.100\)

\(=9000\)

b) \(37.39+78.14+13.85+52.55\)

\(=\) \(37.3.13+26.3.14+13.85+26.2.55\)

\(=\left(37.3.13+13.85\right)+\left(26.3.14+26.2.55\right)\)

\(=13.\left(37.3+85\right)+26\left(3.14+2.55\right)\)

\(=13.196+26.152\)

\(=13.196+13.2.152\)

\(=13.\left(196+2.152\right)\)

\(=13.500\)

\(=6500\)