Lesson 4 of 15
Putting a number in
Show on a big screen2n + 3 is written on a bus ticket. It is not an answer yet. Choose a number for n.
2n + 3 — waiting for a value. Step 1 of 4
2n + 3— waiting for a value.n= 4: 2 × 4 + 3.- 8 + 3.
- 11.
Rule: substitution means swapping the letter for its value. Then calculate: multiply first, then add. 2n means 2 × n. Multiplication is done before addition.
Try n = 0: 2 × 0 + 3 = 0 + 3 = 3. Try n = 10: 2 × 10 + 3 = 20 + 3 = 23. One expression, many answers.
Tap the value of each line in the lab. Then read the working, stage by stage.
Loading lab…
Try the lab to finish this lesson.