This is apparently the number of toys that your baby should have
It can sometimes feel like it is hard to control the toy situation if you have young children.
Some of them are ones parents have bought themselves (occasionally having fallen for those ads about toys that'll stimulate your child's mind or language, etc).
Many of them end up being gifts - whether they're for birthdays, visits from Santa or because granny and grandad have dropped in with "one or two" presents for their beloved grandchild.
That, of course, ends up resulting in one thing: So. Many. Toys. Absolutely everywhere. Toys as far as the eyes can see.
However, it turns out there is actually a definitive number of toys that your little one needs - at least when it comes to babies.
According to social worker and psychotherapist Vicki Sherman, your little one should have "three to five interesting things to play with".
Ms Sherman, who has experience treating and working with infants and children through play therapy, told Romper that they don't even need to be toys specifically sold as toys.
Things like tupperware, balls, pots and pans could also work just as well.
She also revealed what exactly you should be keeping an eye out for when looking for toys for your baby to play with.
She explained that "toys that are tactile" are key, before adding:
"And not just stuffed animals, but things with texture and color."