1298+789怎么简算
问题描述:
1298+789怎么简算
答
1298+789===1300-2+800-11=2100-3=2087
答
=1300-2+700+89
=2000+87
=2087
答
1298+789
=1298+2+700+87
=1300+700+87
=2000+87
=2087
答
1300+790-3