1+2+56+78+9
=(1+9)+(2+78)+56
=10+80+56
=146 nha 
1+2+56+78+9
=(1+9)+(2+78)+56
=10+80+56
=146
\(1+2+56+78+9\)
\(=\left(1+9\right)+\left(2+78\right)+56\)
\(=10+80+56\)
\(=90+56\)
\(=146\)
\(tích\)\(mk\) \(nha\)
\(1+2+56+78+9\)
\(=3+56+78+9\)
\(=59+78+9\)
\(=137+9\)
\(=146\)
\(~~~~~~~~\)
1+2+56+78+9
=(1+9)+(2+78)+56
=10 + 80 + 56
= 146
\(\left(1+9\right)+\left(2+78\right)+56\)
\(10+80+56\)
\(146\)
1+2+56+78+9
=(1+9)+(2+78)+56
= 10 + 80 +56
= 90 +56
= 146
1+2+56+78+9
=3+56+78+9
=59+78+9
=137+9
=146
