← Class 7 unitsComputational Thinking
Class 7
Chapter 4: Expressions using Letter-Numbers
A letter like x or n can stand for an unknown number. We can write expressions with it: 3n means '3 times n'. Like terms — terms with the same letter — can be combined.
Learning outcomes
- Use variables to represent unknowns
- Form and simplify simple algebraic expressions
Activities
- Variable-as-bag concrete tasks
Worked examples
Read through these first, then try the practice below.
Example 1 — Write the expression
I think of a number n. I add 5 to it. Write the expression.
Solution: n + 5.
Example 2 — Combine like terms
Simplify 3a + 2a + 4.
Solution: 3a + 2a = 5a, so the expression is 5a + 4.
Self-do practice
Question 1 of 3 · Score 0/0Simplify 4x + 3x. (write like 5x)
Sign in as a student in this class to save your progress.