Gap between columns with defined width

Question

I have to give the gap between the columns width defined width but the columns shown in a row are 2. How i can resolve?

<section class="container primo">
            <div></div>
            <div></div>
            <div></div>
            <div></div>
            <div></div>
</section>

the css

.container{
        display: flex;
        flex-direction: row;
        gap: 24px;
}
.container div{
                width: calc(100% /3);
}

the column have to be 3, but the first column of the first row is double in size