分类：教育/科学-理工学科-数学
问题：三年级数学你能用简便的方法计算吗?725+726+727+728 
你能用简便的方法计算吗?

725+726+727+728+729+730+731
回答：解法一
(725+726+727+728+729+730+731)+(731+730+729+728+727+726+725)
=(725+731)+(726+730)+(727+729)+(728+728)+(729+727)+(730+726)+(731+725)
=7×(728+728)
725+726+727+728+729+730+731=7×(728+728)÷2
=7×728
=5096.

解法二
725+726+727+728+729+730+731
=(728-3)+(728-2)+(728-1)+728+(728+1)+(728+2)+(728+3)
=728×7
=5096.

解法三
725+726+727+728+729+730+731
=700×7+25+26+27+28+29+30+31
=4900+(28-3)+(28-2)+(28-1)+28+(28+1)+(28+2)+(28+3)
=4900+28×7
=4900+196
=5096.

解法四
725+726+727+728+729+730+731
=720×7+5+6+7+8+9+10+11
=5040+8×7
=5040+56
=5096.