Lab: Tap the Next Operation
An expression appears with its operations as buttons. Tap the operation PEMDAS says to do next — the lab reduces it live.
Which operation is next?
3 + 4 × 2
Tap the operation to perform next.
3 + 8
PEMDAS: ×/÷ outrank +/−.
Try it
Challenge: finish 10 − 2 × 3 with zero mistakes.
Press “New expression” until 10 − 2 × 3 appears, then tap the operations in order.
Mistakes so far: 0
What to notice: the correct “next” button is never the leftmost operation — it is the highest unfinished rung. Train your eyes to scan for grouping and exponents first.
Why it works
PEMDAS is a precedence ladder, not a left-to-right march. Tapping the next operation builds the habit of scanning the whole expression for the highest-priority operation first.