Assume the base value

Let the third number be $100$. The first number is $30\%$ less than $100$, so First Number = $100 - 30 = 70$.

$N_3 = 100, N_1 = 70$

Determine the second number

The second number is $37\%$ less than $100$, so Second Number = $100 - 37 = 63$.

$N_2 = 63$

Calculate the percentage difference

We need to find by what percentage the second number ($63$) is less than the first number ($70$). The difference is $70 - 63 = 7$.

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

Final calculation

Calculating the final percentage: $\frac{7}{70} \times 100 = 0.1 \times 100 = 10\%$.

$\text{Percentage} = 10\%$