Question

 B=24.71+4.6.49+76.13+76.107

Answer 1

 B=24.71+4.6.49+76.13+76.107

=24*71+24*49+76*(13+107)

=24*(71+49)+76*120

=24*120+76*120

=120*(24+76)

=120*100

=12 000

Answer 2

\(B=24\cdot71+4\cdot6\cdot49+76\cdot13+76\cdot107\)
\(\Rightarrow B=24\cdot71+24\cdot49+76\cdot13+76\cdot107\)
\(\Rightarrow B=24\left(71+49\right)+76\left(13+107\right)\)
\(\Rightarrow B=24\cdot120+76\cdot120\)
\(\Rightarrow B=120\cdot\left(24+76\right)\)
\(\Rightarrow B=120\cdot100\)
\(\Rightarrow B=12000\)