2. 3, 4 and 5 constitute the formula of multiplying two digits by two digits, and the product is the largest What are the rules?

2. 3, 4 and 5 constitute the formula of multiplying two digits by two digits, and the product is the largest What are the rules?

52*43=2236
First, make sure that the maximum number of ten digits is 5 and 4 respectively, and then look at the single digits
53*42=2226
52*43=2236