Enter your Sign-on user name and password.

Forgot password?
  • Follow us on:
Loading video...

Start Learning Now

Our free lessons will get you started (Flash® 10 required).
Get immediate access to our entire library.

Sign up for Educator.com

Features Overview

  • Get on-demand access to our complete library
  • Search and jump to exactly what you need to learn
  • Track your progress
  • Download practice and lesson files
  • *Ask questions and get answers from our community & instructors

Properties of Numbers

  • To commute means “to change places”; this helps to explain the commutative properties of addition and multiplication: a + b = b + a and a • b = b • a.
  • To associate means “to gather in groups”; this helps to explain the associative properties of addition and multiplication: (a + b) + c = a + (b + c) and (a • b) • c = a • (b • c).
  • The properties of addition and multiplication often let you do mental computations more easily.
  • The Commutative Property, the Associative Property, and the Identity Property apply to both addition and multiplication of rational numbers.

7.4 + 10 + 3.6 =

  • 7.4 + 3.6 + 10
  • 11 + 10 =

21

21 + 5 + 39 + 5 =

  • (21 + 39) + (5 + 5) =
  • 60 + 10 =

70

3 + 16 + 87 + 14 =

  • (3 + 87) + (16 + 14) =
  • 90 + 30 =

120

25 × 17 × 30 =

  • 25 ×30 ×17 =
  • 750 ×17 =

12,750

2 × 180 × 5 =

  • 2 ×5 ×180 =
  • 10 ×180 =

1,800

5 × 11 × 5 =

  • 25 ×11 =

275

Brendon bought a scarf for $ 3.65, a donut for $ 2.50, and a briefcase for $ 26.35. How much did Brendon spend total?

  • $ 3.65 + $ 2.50 + $ 26.35 =
  • $ 3.65 + $ 26.35 + $ 2.50 =
  • $ 30.00 + $ 2.50 =

$ 32.50

Larissa bought 17 bananas, 34 strawberries, 6 apples, and 53 cherries. How many fruits did she buy total?

  • 17 + 34 + 6 + 53 =
  • (17 + 53) + (34 + 6) =
  • 70 + 40 =

110 fruits

Gregory ran 4 miles on Monday, 7 miles on Tuesday, 6 miles on Wednesday, 9 miles on Thursday, 1 mile on Friday, 1 mile on Saturday, and 2 miles on Sunday. How many miles did he run this week?

  • 4 + 7 + 6 + 9 + 1 + 1 + 2 =
  • (4 + 6) + (7 + 1 + 2) + (9 + 1) =
  • 10 + 10 + 10 =

30 miles

There is a pie - eating contest. Jessica ate 9 pies, Trevor ate 15 pies, George at 11 pies, Natalie ate 5 pies, and Luke ate 10 pies. How many pies were eaten total?

  • 9 + 15 + 11 + 5 + 10 =
  • (9 + 11) + (15 + 5) + 10 =
  • 20 + 20 + 10

50 pies

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

Answer

Properties of Numbers

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

Mathematics: Pre Algebra