Dots and Bars
Part of the Numbers & Operations section of Coddy's Pre-Algebra journey. Lesson 4 of 60.
The board writes two of the four operations differently from a school notebook. Multiplication is a raised dot: 3 × 4 means 3 times 4. The cross sign is avoided because it is too easy to confuse with the letter x, which algebra uses all the time.
Division is a fraction bar: 12 / 4 means 12 divided by 4, which is 3. The number on top is divided by the number underneath. You will meet the bar again when the course reaches fractions, and it is the same idea: a fraction is a division.
The four results have names worth knowing. Adding gives a sum, subtracting gives a difference, multiplying gives a product, and dividing gives a quotient. Word problems use these names, so they are part of reading mathematics.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Numbers & Operations
1Working on the Board
Your First AnswerType the Next LineOne Line at a TimeDots and BarsFriendly ProductsRecap: Board Work4Adding Integers
Adding Two NegativesDifferent SignsZero PairsAdding Several IntegersRecap: Adding Integers2Order of Operations
Multiply Before AddingLeft to RightParentheses FirstBrackets Inside BracketsThe Fraction Bar GroupsRecap: Order of Operations5Subtracting Integers
Add the OppositeSubtracting a NegativePlus and Minus in a RowDistance Between NumbersRecap: Subtracting Integers