complete the ratio table.

Explanation:

Step1: Find the ratio

By looking at the given pairs like $(46, 23)$, $(64, 32)$, $(100, 50)$, we can see that the ratio of the first - column number to the second - column number is $2:1$. That is, if the number in the first column is $x$ and the number in the second column is $y$, then $\frac{x}{y}=2$.

Step2: Find the missing number in the second row

If the number in the first column is $20$ and the ratio of the first - column number to the second - column number is $2:1$, let the missing number be $y$. Then $20\div y = 2$, so $y=\frac{20}{2}=10$.

Step3: Find the missing number in the first row

If the number in the second column is $1$ and the ratio of the first - column number to the second - column number is $2:1$, let the missing number be $x$. Then $\frac{x}{1}=2$, so $x = 2$.

Answer:

The first - row missing number is $2$, and the second - row missing number is $10$.