379×0.38＋159×6.21＋3.79×121
=3.79×（38＋121）＋159×6.21
=3.79×159＋159×6.21
=159×（3.79＋6.21）
=159×10
=1590
379乘0.38加159乘6.21加3.79乘121
379×0.38＋159×6.21＋3.79×121
=3.79×（38＋121）＋159×6.21
=3.79×159＋159×6.21
=159×（3.79＋6.21）
=159×10
=1590