1. The problem asks: If the decimal moves one place to the left, which operation does that represent and why? 2. When a decimal point moves one place to the left in a number, the value of the number becomes 10 times smaller. 3. This is because moving the decimal left divides the number by 10. 4. The operation that divides a number by 10 is division. 5. Therefore, moving the decimal one place to the left represents division by 10. 6. The correct answer is: "Division, because the decimal shifts left when you divide, making the number’s value 10 times less."