Equal width columns Bootstrap v4?

Question

css

Hello! Bootstrap v4 has the ability to set columns. When testing the layout in Firefox, there was a problem with columns of the same width: three columns should be displayed in one row, and in firefox such columns are displayed one below the other, i.e. each column stretches to the full width of the wrapping container. Tell me how to solve this problem?
Below are screenshots that clearly demonstrate how columns of the same width are displayed in firefox and in chrome

Answer 1

Wrap in div class="row"
Give "exact" column proportions, col-4 etc.