1 / 9

1-4 6 th grade math

1-4 6 th grade math. Addition Properties. Objective. To use addition properties and mental math strategies to compute mentally Why? To help you add mentally and get a rounded estimate to an addition problem. California State Standards.

gray-cooper
Télécharger la présentation

1-4 6 th grade math

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. 1-46th grade math Addition Properties

  2. Objective • To use addition properties and mental math strategies to compute mentally • Why? To help you add mentally and get a rounded estimate to an addition problem.

  3. California State Standards AF 1.3: Apply … the commutative, associative properties to evaluate expressions … MR 2.0: Use strategies, skills, and concepts in finding solutions.

  4. Vocabulary • Mental Math • The process of producing an exact answer without pencil and paper or other computational aids. • Commutative Property • The order in which numbers are added does NOT affect the sum. (Just which the order.) • 8 + 12 = 12 + 8 • Associative Property • The way in which addends are grouped does NOT affect the sum. (Keep the same order, but switch around the parentheses.) • 7 + (11 + 5) = (7 + 11) + 5 • Identity Property • The sum of any number and zero (0) is that number. • 45 + 0 = 45

  5. Vocabulary • Compatible Numbers Method • Group together numbers that are easily computed mentally • 76 + 68 + 14 = (76 + 14) + 68 = 90 + 68 = 158 • Break-Apart Method • Break-apart numbers to have easier numbers to work with. • 128 + 64 = (128 + 60) + 4 = 188 + 4 = 192 • Compensation Method • Change one number to make it easy to use. Then change the other number to compensate (adjust). Imagine a balance. • 173 + 16 = (173 + 7) + (16 – 7) = 180 + 9 = 189

  6. How to Use Addition Properties 1) Decide whether to use the Compatible Number Method, or Break-Apart Method or Compensation Method 2) Apply the rules to solve either one. 3) Check your work. Choose a strategy and compute mentally. A) 54 + 29 Use the break-apart strategy. = (54 + 20) + 9 = 74 + 9 = 83 B) 41 + 55 + 9 Use the compatible numbers strategy. = (41 + 9) + 55 = 50 + 55 = 105

  7. Try It! Choose a strategy and compute mentally. • 28 + 74 + 32 • 325 + 225 • 88 + 64 • 124 - 79 • Compatible Numbers = (28 + 32) + 74 = 60 + 74 = 134 2) Compensation Method = (325 – 5) + (225 + 5) = 320 + 230 = 550 3) Break-Apart Method = (88 + 60) + 4 = 148 + 4 = 152 4) Compatible Numbers = (124 - 4) – (79 – 4) = 120 – 75 = 45

  8. Objective Review • To use addition properties and mental math strategies to compute mentally • Why? You can now add mentally and get a rounded estimate to an addition problem. Addition properties and mental math strategies can be used to find exact answers without using pencil and paper.

  9. Independent Practice • Complete problems 6-17 • Copy original problem first. • Show all work! • If time, complete Mixed Review: 18-23 • If still more time, work on Accelerated Math.

More Related