Question 16
An “interesting” number is a four-digit whole number whose first two digits, read as a two-digit number, equal the product of its tens and units digits. For example, 1535 is interesting because $3\times5=15$, but 6623 is not because $2\times3=6$, which is not 66. What is the difference between the largest and smallest interesting numbers?
Answer format: enter the integer answer without units. Leading zeros are optional; the original paper uses four-digit boxes.
Answer format: enter the integer answer without units. Leading zeros are optional; the original paper uses four-digit boxes.