Measure
&
Estimate

Well, humans have found ways to measure different things.

They use different units to measure how long things are,

and there have been times when they would measure things in terms of bits of the body,

like the length of a foot, or a stride, or an arm's length.

But one person's foot isn't quite like another's,

so they used rulers which all had the same length marked on them,

so that everyone knew what everyone meant by one foot long.

And along with rulers they made measuring tapes, and ropes

to measure long distances, and keep everything the same,

but different countries were still using different units to measure things,

so in the end they all agreed to use metres and centimetres as the units of measure.

But that was just for measuring length.

They also needed to agree on a way to measure weight.

In the markets they used to weigh their goods on scales,

but how could you know for sure how much you were you were getting for your money?

It used to be that the king would send people to the markets to test the different weights they were using,

and along with agreeing to use metres and centimetres,

people also agreed to measure weight using grams and kilograms.

And people made wonderful machines for measuring,

so they could measure distances smaller than the width of a human hair.

Whether it is how long or how heavy, they can measure things that they can't see with their eyes

or feel with their fingers.

Yet most of the time, whatever they are doing, they don't have to measure things that close.

Most of the time, in one way or another, the only number you need is something close.

So if something seems to measure just a little bit more or less than five,

saying five is possibly close enough.

And especially with bigger numbers, like sheep in a field,

when you know that if you don't count them all it's just going to be a guess,

the important thing is to be able to estimate how close your guess is likely to be.

To estimate really just means to make your best guess,

using the results from times when you guessed before,

and how close you were on those occasions.

Estimates aren't expected to be exactly right,

but if they are good they should be close enough to not be too wrong.