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Chapter 5 · Expressions · page 26 of 68

What x means

levelGrade 6
standard6.EE.B
practiceTwo-step equations

A variable is a number you do not know yet, or a number that can vary. Writing 2x means two of that number. Writing x + 3 means three more than it. Nothing about the letter is special. It could be any letter.

How to use it

  1. Read 2x as "two times x." A number next to a letter means multiply.
  2. When you learn the value, replace the letter with it and compute.

Example

if x=5:2x+3=2⋅5+3=13\text{if } x = 5: \quad 2x + 3 = 2 \cdot 5 + 3 = 13
xy means x×yxy \text{ means } x \times y

Where it goes wrong

  • Reading 2x as "two and x" or 2 + x.
  • Thinking x must be the same number in every problem. It resets each time.

Related

Terms and coefficientsWhat an equation is
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