I was told in 4th grade that the oldest game in the world is Mancala. I don't think this is true anymore because the earliest evidence of the game is from the 6th or 7th century AD, whereas games such as Senet, Pachisi, Go, Backgammon, and Chess were all played before this time [link].
But that doesn't say that people in Africa didn't play Mancala before the 6th or 7th century. We just don't have physical proof that they played it before all the others. For all we know, they could have just dug holes in the ground and played with pebbles they found. And they could have played it that way for centuries before actually making a playing board out of pottery or wood.