The Mysterious Number Machine
For Years 4–6 · 🏅 20 points for correct answers
A number machine does the following two steps in order:
Step 1: Multiply the input by 3.
Step 2: Subtract the input from the result of Step 1.
When I put in a number, the output is 84.
What was my input?
INPUT
?
× 3
then
− input
OUTPUT
84
💡 Need a hint? Click to reveal
Think about what the two steps together do to your number. Can you write it as a single multiplication?