This activity was also taken from https://www.youcubed.org/tasks/how-close-to-100/. You probably figured out that I love the site. Now that I read the instructions carefully, we did not follow them (it should be much more fun as a game as they intended).
Supplies: graph paper where you outlined a 10x10 square and 2 dice.
Modified supplies: if you don't have 2 dice, the cards Ace through 6 from a deck of cards work too. The advantage is that you can use higher or lower numbers depending on how young your kids are. I used a 10x10 pegboard - my kids love pegboards.
What to do: the child rolls the 2 dice or pulls out two cards. She has to fill as many squares or put in as many pegs as the product of the two numbers (we didn't talk about products or even call them such). For example, if the numbers are a 2 and a 3, I just told my 5 year-old to do 2 rows of 3 or 3 rows of 2.
I used four-sided dice with my 5 year-old and she seemed happy with it. If you don’t have a four-sided die, take out the aces through 4 cards of a deck of card. It should work well.