Henry Ernest Dudeney/Puzzles and Curious Problems/87 - Reversing the Digits/Solution

Puzzles and Curious Problems by Henry Ernest Dudeney: $87$

Reversing the Digits

What $9$-digit number, when multiplied by $123\, 456 \, 789$, gives a product ending in $987 \, 654 \, 321$?

Solution

$989 \, 010 \, 989 \times 123 \, 456 \, 789 = 122 \, 100 \, 120 \, 987 \, 654 \, 321$

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Solutions: $87$. -- Reversing the Digits
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Answers: $124$. Reversing the Digits