Lesson 4 of 5 · 8 minutes

Changing a variable's value

A variable made with let can receive a new value. This is reassignment.

score = score + 1; reads the current score, adds one, and puts the result back into the same box. The label stays. The value changes.

Use const when a value should not change. A const box cannot be reassigned. This protects values that should stay fixed.

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Run it twice. Each run starts the whole program again, so it prints 1 both times.

Quick check

Which keyword allows a value to be reassigned?

letconstconsole.log

Choose one answer.

Why does a fresh run print 1 again, not 2?

Each run starts again with score equal to 0.The + sign can only add once.Variables cannot change.

Choose one answer.

You can now change a variable's value — and lock one with const when it should stay fixed.