Question

23乘以23加69乘69减69乘5的简便计算？

Answer 1

23*23+69*69-69*5
=23^2+9*23^2-23*15
=10*23^2-23*15
=23（230-15）
=23*215
=（25-2）*215
=21500/4-430
=5375-430
=4945

Answer 2

23×23+69×69-69×5
=23×（20+3）+69×（69-5）
=23×20+23×3+69×64
=460+69+69×64
=460+69×（1+64）
=460+69×65
=460+（70-1）×65
=460+70×65-65
=460+4550-65
=5010-65
=4945