Lesson video
Start here.
Press play for Monday’s lesson on variables and expressions. Then catch the Bandit Error further down the page and finish with the Mission.
September · Week 1 · Day 1
Variables & Expressions
Meet the letter without trying to solve it. Today is about reading algebra clearly: what a variable stands for, what makes something an expression, and why 3x means three times x.
Three things to lock in.
These are the ideas the Mission asks you to use.
VariableA letter or symbol that stands for a number.
ExpressionA math phrase made of numbers, variables, and operations. No equals sign required.
3xRead it as “three times x.” The multiplication is implied.
✗ Today’s Bandit Error
Bandit adds what cannot be added.
Bandit sees the 3 and the 7 and tries to mash them together. Fast instinct. Wrong category.
✗ 3x + 7 = 10x
✓ 3x + 7 stays 3x + 7
3x counts x-amounts. 7 counts ones. They are different kinds of terms, so they do not combine.
Free Mission
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Monday’s Mission has 10 problems plus the Mission Debrief so you can check your reasoning when you finish.
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