Think of it like this: 100 = 10 * 10 10,000 = 100*100 When you Square 10, the product has the combined number of zeros. For 100,000, the number has an odd number of zeros (5). Therefore, you should think of it as something between 300 and 400, since 300 squared is 90,000 and 400 squared is 160,000. I would give them a range - probably around 300-315.