Ordinal Numbers

1Summary 重點摘要

Order in a queue: first, second, third... use 第.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Step 1: Count from the frontIn a queue, ordinal numbers are counted starting from the head of the line: the person at the front is first, then second, third, and so on. Example: 5 pupils stand in a line; count from the very front: first, second, third, fourth, fifth. Point and count one by one so nobody is counted twice or missed. Why start from the head? Ordinals show position, and a position needs a clear starting point to stay tidy. A common mistake is counting from the middle or the back of the line, which gives a different place from everyone else.
2. Step 2: Use ordinal wordsWhen we talk about position, the ordinal word goes with the number, and this is what makes ordinals different from ordinary numbers. Example: standing in the third place of a queue, we say 'third', not just 'three'; fifth in the ticket line, we say 'the fifth one'. The ordinal word tells people we mean a position, not an amount. A common mistake is mixing position with quantity, for example 'my third book' and 'my three books' mean completely different things: the first says which book, and the second says how many.
3. Step 3: People before position NIf you know someone's position, subtract 1 to find how many people stand in front. Example: Ming is third; 3 - 1 = 2, so 2 people are in front of him. Why subtract 1? The people in front are first and second, not including himself, so his own place must be taken away. In the same way, a person seventh in line has 7 - 1 = 6 people in front. A common mistake is taking the position number as the number of people in front, as if being third meant 3 people ahead; in fact one of those 3 places is his own.
4. Step 4: Watch the directionThe same thing can have different ordinal numbers when counted from different ends, so say clearly where the counting starts before answering. Example: 4 cups in a row; counted from the left the red cup is second, but from the right it is third, and whether the question says 'from the left' or 'from the right' completely changes the answer. Why? Ordinals depend on the starting point, and a new starting point gives a new position. A common mistake is answering without checking the direction; always find the starting point the question names before counting.
5. Step 5: Short forms in EnglishEnglish ordinal numbers have special short forms made by adding two letters after the number. Example: first is written 1st, second 2nd, third 3rd, and after fourth most numbers take th, such as 4th, 5th and 6th; 11, 12 and 13 are special and are written 11th, 12th and 13th. Why learn these forms? Textbooks and exercises in English often mark order this way. A common mistake is writing 3rd as 3st or 2nd as 2th; remember the rule: one, two and three are special, and the others take th.
6. Step 6: Find your own positionTo find your own place, add 1 to the number of people in front of you. Example: 4 people stand in front of you; 4 + 1 = 5, so you are fifth. Why add 1? The 4 people in front hold first to fourth places, and the very next place, which is fifth, is yours. This is just the reverse of subtracting 1: position minus 1 gives the people in front, and the people in front plus 1 gives the position. A common mistake is forgetting the 1 and thinking 4 people ahead make you fourth; in fact fourth is the classmate just in front of you.

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Use ordinal words for order.
• Count from the front: first, second, third...
• Position N has N - 1 people in front.
• Say the direction you count from.
• English forms: 1st, 2nd, 3rd, 4th.