Question

1. \the sum of three and a number, divided by three, is five.\

Explanation:

Step1: Define the variable

Let the number be \( x \).

Step2: Translate the sentence into an equation

The sum of three and a number is \( 3 + x \), divided by three is \( \frac{3 + x}{3} \), and this equals five. So the equation is \( \frac{3 + x}{3} = 5 \).

Step3: Solve the equation

Multiply both sides of the equation by 3: \( 3 + x = 5\times3 \)
Simplify the right side: \( 3 + x = 15 \)
Subtract 3 from both sides: \( x = 15 - 3 \)
Calculate the result: \( x = 12 \)

Step4: Check the solution

Substitute \( x = 12 \) into the original expression: \( \frac{3 + 12}{3} = \frac{15}{3} = 5 \), which matches the given result.

Answer:

The number is \( \boldsymbol{12} \)