Visual Estimation

Visual Estimation is finding a value that is close enough to the right answer.

  • We are not trying to get the exact right answer
  • What we want is something that is good enough (usually in a hurry)

Example: How many objects are here:

How Many Objects

We could count them, but what if we don't need an exact answer, just one that is close enough?

Have a go! Try to make a quick guess how many.

Answer: 48


As well as looking, we should also be thinking.

Example: If the small box has an area of "1" what is the area of the big box?:

estimate area

Try "measuring by eye" the width and height, then multiplying ... what do you come up with?

Answer: About 7×4 = 28

Estimating Counts, Lengths and More

It is a very useful skill to be able to estimate how many things we see, or how long something is or how big something is, and so on.

Examples:

  • How much wrapping paper do you need to wrap a large box?
  • How much bread do you need to make sandwiches for all your friends?
  • How many people in the room?
  • How thick should you make each slice of cake at a party?
  • How much paint do you need to paint a wall, or table?

Experience

Knowing the usual size of things can also help.

And there is also a special trick to Estimate How Far Away.

Games

Being good at this takes practice and experience.

So there are the Estimation Games to help you get started!

(Have fun!)