Substitution into formulae

What you'll learn

1. 1

   Imagine you have a robot 🤖 that follows a rule. The rule says 'If I give you a number, double it and add 1'. That's like a formula!

2. 2

   If the formula is '2 × ? + 1', what does the robot say when you give it 4?

3. 3

   Drag the number 5 into the formula '3 × ? + 2' to see what the robot says.

4. 4

   Let's do one together: Substitute 6 into the formula '4 × ? - 3'.

5. 5

   Now you try: substitute 7 into '5 × ? - 2' and find the answer.

6. 6

   What do you get when you substitute 8 into '3 × ? + 4'?

7. 7

   Substitute 10 into '2 × ? + 5'. What's the answer?