=10(1+7+2)+8x8+8+8
=10x10+8(8+1+1)
=100+8x10
=100+80=180
10 + 10 x 7 + 10 x 2 + 8 x 8 + 8 + 8
= 10 x 8 + 10 x 2 + 8 x 8 + 8 + 8
= 10 x ( 8 + 2 ) + 8 x 10
= 10 x 10 + 80
= 100 + 80
= 180
10+10x7+10x2+8x8+8+8
= 10x1+10x7+10x2+8x8+8x2 ( anh ghi rõ cho em dễ hiểu hơn nha )
= 10x(1+7+2)+8x(8+2)
= 10x10+8x10=100+80=180