1 / 8

Using Estimation

Using Estimation. Lesson 2.5. Clustering. When you have several numbers that are nearly the same, you can round them all the same way and multiply. EXAMPLE: 876 906 + 894. These are all close to 900, and there are 3 numbers. So, we can just multiply 900 x 3.

shaw
Download Presentation

Using Estimation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Using Estimation Lesson 2.5

  2. Clustering • When you have several numbers that are nearly the same, you can round them all the same way and multiply. EXAMPLE: 876 906 + 894 These are all close to 900, and there are 3 numbers. So, we can just multiply 900 x 3. Think 9 x 3. You get 27. Now add the two 0’s from 900, and you get 2,700.

  3. Another Example of Clustering 1,485 1,513 1,499 1,508 1,523 1,500 15 x 5 x 5 7,500 75 +

  4. Compatible Numbers • Compatible number are substitute numbers that divide and multiply easily. 5 is compatible with (it divides into) 25, so change 2,459 to 2,500. 5 2,459 500 5 2,500

  5. Another Compatible Number 28 into 62? Who knows! Instead, think of it as 30 into 6,000, since 3 and 6 are compatible. 28 6,241 200 30 6,000

  6. Rounding 400 1. Find the place you’re rounding to. 389 2. Look one space to the right. If the next door number is 0-4, then you leave the number in the box alone. If the next door number is 5-9, then raise the number in the box by 1. - 43 40 360 3. The rest of the numbers become 0’s. 4. Repeat.

  7. One More Example of Rounding 2,000 1,789 3,000 3,396 9,000 + 8,519 14,000

  8. Just Remember... The idea is to make the problem easier. Use clustering if all of your numbers are close to each other. Use compatible numbers when dividing. If all else fails, just round the numbers so that they end in zeroes. The End

More Related