Recall that:
[tex]a\times n=\underbrace{a+a+\cdots+a\,}_{$ n $\text{ times}}.[/tex]Since the pet store has k tanks with 26 fish on each tank, then the pet store has:
[tex]\underbrace{26+26+\cdots+26\,}_{k\text{ times}}[/tex]fish in total.
Now, notice that:
[tex]\underbrace{26+26+\cdots+26\,}_{k\text{ times}}=26\times k=26k.[/tex]Answer:
[tex]26k.[/tex]
