Type the missing number to complete the proportion: 9 stamps on 1 sheet = ? stamps on 2 sheets.
Understand the Problem
The question is asking to find the missing number that completes the proportion relating the number of stamps on sheets. It gives a ratio of 9 stamps on 1 sheet and asks how many stamps would be on 2 sheets.
Answer
The missing number is $18$ stamps.
Answer for screen readers
The missing number is $18$ stamps.
Steps to Solve
-
Set up the proportion We have the ratio of stamps to sheets. It can be expressed as:
$$ \frac{9 \text{ stamps}}{1 \text{ sheet}} = \frac{x \text{ stamps}}{2 \text{ sheets}} $$ -
Cross-multiply To find the missing number, cross-multiply:
$$ 9 \times 2 = 1 \times x $$
This simplifies to:
$$ 18 = x $$ -
Solve for x From the equation $18 = x$, we find:
$$ x = 18 $$
The missing number is $18$ stamps.
More Information
This shows that if there are 9 stamps on 1 sheet, then there would be 18 stamps on 2 sheets. This maintain the ratio consistently.
Tips
- Forgetting to cross-multiply: Always remember to apply cross-multiplication correctly to maintain the equality.
- Mixing up the ratios: Ensure that the numbers correspond correctly to sheets and stamps as per the setup.
