4.51.7+2.86.7+12.2.7
= 2.7.2.51+ 2.2.7.43+ 2.2.7.6
=2.2.7 .( 51+43+6)
= 28 . 100
= 2800
\(4.51.7+2.86.7+12.2.7=\left(4.51.7\right)+\left(2.86.7\right)+\left(12.2.7\right)=1428+1204+168=2632+168=2800\)
4.51.7 + 2.86.7 + 12.2.7
= 2.2.51.7 + 2.7.86 + 2.7.12
= 2.7.102 + 2.7.86 + 2.7.12
= 2.7 ( 102 + 86 + 12)
= 14 . 200
= 2800