The numbers less than 4 are 1, 2, and 3. From the table, a 1 was rolled 6 times, a 2 was rolled 4 times, and a 3 was rolled 8 times. Therefore, a number less than 4 was rolled $6+4+8=18$ times

It is given that the number cube was rolled 50 times.

The relative frequency of rolling a number less than 4 is:

а$(\text{\u0430requency of rolling a number less than 4 total number of rolls})\times 100$

Since a number less than 4 was rolled 18 times and the total number of rolls is 50, then the relative frequency of rolling a number less than 4 is:

$\frac{18}{50}\times 100\mathrm{\%}=18\times \frac{100}{50}\mathrm{\%}=18\times 2\mathrm{\%}=36\mathrm{\%}$