Assume the third number

Let the third number be $100$.

$\text{Third}\ \text{Number} = 100$

Calculate the first and second numbers

The first number is $30\%$ less than $100$, which is $100 - 30 = 70$. The second number is $37\%$ less than $100$, which is $100 - 37 = 63$.

$Number_1 = 70, Number_2 = 63$

Find the required percentage

The question asks what percentage of the first number ($70$) is the second number ($63$).

$\text{Percentage} = \frac{63}{70} \times 100$

Final calculation

Simplifying the fraction: $\frac{63}{70} = \frac{9}{10}$. Multiplying by $100$ gives $90\%$.

$0.9 \times 100 = 90\%$