ABE Math Tutorials/Whole numbers/Introduction to algebra
Introduction to Algebra
Whole numbers 
Introduction  Place value  Rounding  Long addition & subtraction  Long Multiplication  Long division  Expressing operations  Word problems  Order of operations  "Setup" problems  Cost and distance problems  Introduction to algebra  Powers of 10  Estimation  Not enough info  Homework

Introduction
You should have completed the lesson on Cost and Distance Problems before you work on this lesson. In that lesson, we started to work with the cost formula and the distance formula. Formulas are a handy way of showing how certain numbers are related, like distance, rate, and time. In a formula, we use a letter (like d, r, or t) to indicate the number that we need to find.
Objective
Letters are actually used a lot in mathematics. Letters are used to indicate "the number that we need to find" in many calculations. In elementary or public school, you probably saw question marks ( ? ) used the same way, like this:
Summary
instead; and we  cell2  cell3 
cell3  cell4  cell5 
4 + 3 = ? Or maybe like this: 7 + ? = 9 But in the higher grades, we use a letter (often the letter "x") instead; and we call this algebra. Here are a few examples: Question: 4 + x = 10 Answer: x = 6 because 4 + 6 = 10 Another one: Question: x  5 = 8 Answer: x = 13 (...because 13  5 = 8) Template:Activity2Are you fine?
We can use " x " with multiplication and division problems, too: 7(x) = 21
Conclusion
Remember that we read this question as "7 times x = 21. In this case, x = 3, because 7 x 3 = 21 And, for division: 32 ÷ x = 4 x = 8 (...because 32 ÷ 8 = 4)