72x0.81 + 10.4 (simple calculation)
72*0.9*0.9+10.4
Skillful calculation 57x99 + 62, skillful calculation, 1999 + 999x999
57*100—-57+62=5705
999+999*999=999*1000
Original formula = 1000 + 1000 * 999 = 1000000
Journey to the West
The eighty first difficulty is to wet the Scriptures when the Tongtian River is overturned
Tongtianhe turtle