Basic Algebra/Introduction to Basic Algebra Ideas/Simple Operations
Vocabulary[edit | edit source]
- Operation
- Equals Sign
- Adding
- Subtracting
- Multiplying
- Dividing
Lesson[edit | edit source]
An operation is a thing you do to numbers. You use signs like: +, –, ×, or ÷ for operations.
The equals sign is not an operation. You use the " = " sign for the equals sign. It is a special sign that you put between two things that are the same.
Adding[edit | edit source]
Adding is a way to put two numbers together. You use the " + " sign for the adding operation. If you have 5 apples and a friend has 6 apples, you and your friend have 11 apples. This is 5 + 6 = 11 using the signs of Mathematics, and is read "five plus six equals eleven".
Order is not important when adding. 2 + 3 is the same as 3 + 2.
Subtracting[edit | edit source]
Subtracting is a way of taking a number from another number. It is the opposite of adding. You use the " – " sign for the subtracting operation. If you have 5 apples and give 3 to a friend, you then have 2 apples left. This is 5 – 3 = 2 using the signs of Mathematics, and is read "five minus three equals two".
Order is important when subtracting. 3 – 2 is not the same as 2 – 3.
Multiplying[edit | edit source]
Multiplying is a way of adding a number many times. You use the " × ", " • " or " * " sign for the multiplying operation. If you have 4 apple trees and every tree has 25 apples, you have 100 apples. This is 4 × 25 = 100 or 25 + 25 + 25 + 25 = 100 in the signs of Mathematics. The first way is shorter and easier to use.
Multiplying 25 by 4 is the same as adding 25, 4 times or adding 4, 25 times.
4 x 25 = 100 should be read "four times twenty-five equals one hundred".
Order is not important when multiplying. 2 × 3 is the same as 3 × 2.
Dividing[edit | edit source]
Dividing is a way of subtracting a number many times. It is the opposite of multiplying. You use the " ÷ " or " / " sign for the dividing operation. If 3 friends take an equal part of a bag of 12 apples, every friend gets 4 apples. Or, you may take away (subtract) 3 apples from the bag of 12 apples, exactly 4 times until the bag is empty. This is 12 ÷ 3 = 4 or 12 – 3 – 3 – 3 – 3 = 0 in the signs of Mathematics.
12 ÷ 3 = 4 should be read "twelve divided by three equals 4".
Order is important when dividing. 3 ÷ 2 is not the same as 2 ÷ 3.
Example Problems[edit | edit source]
- 3 + 4 = 7
- 5 – 3 = 2
- 6 × 2 = 12
- 13 + 14 = 27
- 21 – 9 = 12
- 8 × 3 = 24
Practice Games[edit | edit source]
- Arcademics Grand Prix (Multiplication)
- Arcademics Jet Ski (Addition)
- Arcademics Sailboat (Subtraction)
- Arcademics Drag Race (Division)
Practice Problems[edit | edit source]
