Henry Ernest Dudeney/Puzzles and Curious Problems/171 - Multiplication Dates

Puzzles and Curious Problems by Henry Ernest Dudeney: $171$

Multiplication Dates

In the year $1928$ there were $4$ dates which, when written in the form dd/mm/yy,

the day multiplied by the month equal the year.

These are 28/1/28, 14/2/28, 7/4/28 and 4/7/28.

How many times in the $20$th century -- $\text {1901}$ – $\text {2000}$ inclusive -- does this so happen?

Or, you can try to find out which year in the century gives the largest number of dates that comply with the conditions.

There is one year that beats all the others.

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Arithmetical and Algebraical Problems: Various Arithmetical and Algebraical Problems: $171$. -- Multiplication Dates
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Arithmetical and Algebraical Problems: Miscellaneous Puzzles: $236$. Multiplication Dates