Track quiz
Show on a big screenEight ideas, eight checks. The table comes first, so nothing has to be remembered cold.
| Idea | How it goes |
|---|---|
| One mark each | One stroke per thing counted, and nothing else. |
| Bundles | Bundles times size, plus the loose marks, give back the count. |
| Roman symbols | Symbols add. Six pairs take away: IV, IX, XL, XC, CD and CM. |
| Roman examples | XXXVII is 10+10+10+5+1+1 = 37. IV is 5 − 1 = 4. |
| The column | A 5 is worth 5, 50 or 500, by column. |
| The empty place | With no zero, 205, 25 and 250 all write the same. |
| Ten symbols | A column holds one of ten symbols, 0 to 9. One more than 9 moves to the next column. |
| Cost of adding | Columns cost about a mark per digit. For these sums, symbols cost at least three times as many. |
A row of 20 strokes was written as balls were bowled. What does the row record?
23 items are bundled in fives. How many full bundles, and how many loose?
XIV and XVI use the same three symbols. What are they worth?
What is digit 5 worth in the ones, tens and hundreds column?
A system has no symbol for an empty column. How does it write 205, 25 and 250?
A frame holds 4 thousands, 0 hundreds, 7 tens and 3 ones. What number is that?
Adding 8 and 9, which route costs more, and by how much?
How many of the seven symbols does 1,23,45,678 need?
Part I, Chapter 3 is A Story of Numbers. Read it in your book. Ask two questions. What is a symbol worth? Does its place matter?
Next: Quadrilaterals — four sides, four corners, and the names a shape earns.
Reveal every answer to finish this lesson.