Final answer:
The quotient of a number plus 6 and 3 is written as (x + 6) ÷ 3 or as a fraction (x + 6) / 3, with 'x' representing the unknown number.
Step-by-step explanation:
To write the quotient of a number plus 6 and 3 using a variable expression, you can use the letter 'x' to represent the unknown number. The word 'quotient' indicates division in mathematical terms. Hence, the expression would be:
(x + 6) ÷ 3
This means you take the number 'x', add 6 to it, and then divide the result by 3. If you prefer to see it without the division sign, you can also write it as a fraction:
(x + 6) / 3
In both cases, the quotient represents the division of the sum of an unknown number and 6 by 3.