How to calculate the simple algorithm of 397 × 101-397

How to calculate the simple algorithm of 397 × 101-397


397×101-397
=397*(100+1)-397*1
=397*100
=39700



Simple operation method of 234 * 1200 + 7600 * 12


234*1200+7600*12
=1200×234+1200×76
=1200×(234+76)
=1200×300
=360000