How do you estimate an irrational number? why might you need to be able to estimate an irrational number?

To estimate an irrational number look for a rational number that is close to an irrational number. For instance, is an irrational number and it would be hard for us to calculate the value in our head but we can estimate pretty quickly and get a ball park figure or a number that is close enough.
To get a number close enough we ask our self what is a square root that is close that we know. we know that is close and we know the answer is 2 so the has to be under 2 so we can estimate it is 1.7 or we can estimate it is 1.8 or 1.69999999. Estimation allows use to figure things out quickly and help solve irrational number, which can be hard to figure out.