238+320+262
=230+8+320+260+2
=230+320+260+8+2
=550+260+10
=810+10
=820
88+12
=80+8+10+2
=80+10+8+2
=90+10
=100
58+12
=50+8+10+2
=50+10+8+2
=60+10
=70
用简便方法计算：238＋320＋262 88＋12 58＋12
238+320+262
=230+8+320+260+2
=230+320+260+8+2
=550+260+10
=810+10
=820
88+12
=80+8+10+2
=80+10+8+2
=90+10
=100
58+12
=50+8+10+2
=50+10+8+2
=60+10
=70