Question

请问一下79x79十179x21用简便计算该怎么算呢？

Answer 1

79X79+179X21
=79x79+(100+79)ⅹ21
=79x79+100x21+79x21
=79ⅹ(79+21)+100X21
=79X100+100ⅹ21
=100X(79+21)
=100x100
=10000

Answer 2

79×79＋179×21
＝79×（100－21）＋（100+79）×21
＝79×100－79×21＋100×21＋79×21
＝（79+21）×100
＝100×100＝10000