Uncertain number

An uncertain number is a number that we don't know exactly. You know how you count your toys and you know you have 10 stuffed animals? That's a certain number because you know exactly how many you have. But sometimes, we are not sure how many things we have. For example, if you put 5 candies into a jar and then your sister put some more in, you might not know exactly how many candies there are because you can't see inside the jar. That's an uncertain number. It could be 6, 7, 8, or even more candies in the jar, but we don't know for sure. Uncertain numbers happen a lot in science and math, and we do our best to figure out the range of possibilities that the number could be.