4x51x7 + 2x86x7 + 2x2x7
= 204x7 + 172x7 + 4x7
= ( 204 + 172 + 4 ) x 7
= 380 x 7
=2660
4x51x7+2x86x7+12x2x7=
(4 x7)x51+(2x7)x86+(2x7)x12=
28x51+14x86+14x12=
14x2x51+14x86+14 x12=
14x102+14x86+14x12=
14x(102+86+12)=
14x200=
2800
4 x 51 x 7 + 2 x 86 x 7 + 2 x 2 x 7 = 2660 nha 
Trần Quốc Trung ! ! !
4 x 51 x 7 + 2 x 86 x 7 + 2 x 2 x 7
= 4 x ( 2 + 2 ) x ( 2 + 2 ) x 7 x 51 x 86
= 4 x 4 x 4 x 7 x 51 x 86
= 1 964 928
\(\text{Phép tính : 4 x 51 x 7 + 2 x 86 x 7 + 2 x 2 x 7 = 2660}\)
