Track quiz
Eleven ideas, eleven questions. The table is here if a question stalls.
| Idea | How it goes |
|---|---|
| Hold a number | n stands for a number nobody has chosen yet. It can be any number. |
| Carry a rule | Four arms of n, one middle tile: 4n + 1. |
| Drop the times sign | 3n is 3 × n, written shorter. |
| Take a value | Swap the letter, multiply first, then add. |
| Match, or not | Same at every value is the same expression. One match proves nothing. |
| Sort by letter part | Like terms share a letter part. Plain numbers are like each other. |
| Join two of them | String every term, then collect. A minus reaches the whole bracket. |
| Read a situation | A per-one amount, plus a once-only amount: 40t + 15. |
| Write a formula | A formula is a rule written in letters. A regular polygon has equal sides and equal angles. With n sides of length a, its perimeter is n × a. |
| Name a calendar square | Call the top-left date a. Right of it is a + 1. Below it is a + 7. Across the diagonal is a + 8. Each diagonal adds to 2a + 8. |
| Test a simplification | To test a simplified line, put the same number into both sides. Different answers mean a mistake. One match proves nothing. |
A tin holds some marbles. The count is called n. What can n be in n + 3?
The plus pattern has four arms of n tiles. It has one middle tile. How many tiles at step 10?
What is 3n when n holds 5?
What is 2n + 3 when n holds 4?
Someone claims 2n + 3 and 5n are the same. Both give 5 at n = 1. Are they?
Which of these may be collected into a single term?
What does (5n + 3) − (2n + 1) collect to?
An auto ride starts at ₹30 and adds ₹12 for each kilometre. What is the fare for k kilometres?
A regular octagon has 8 equal sides, each s cm long. Which formula gives its perimeter?
The top-left date of a calendar square is w. What is the bottom-right date?
Someone says 5 − (2 − k) = 3 − k. At k = 0 both sides give 3. What should you do?
Part I, Chapter 4 is called Expressions using Letter-Numbers. Open it, and see which page you recognise first.
Next: Parallel and Intersecting Lines. Lines that cross, lines that never do. And the angles a third line makes.