Use ordinal numbers from first to tenth

What you will learn

• Use ordinal numbers from first to tenth

Models used: number sentences, stories, diagrams.

Before you start

• Continue number patterns

Where are you in the queue?

These children are waiting in a line. Start at the front, on the left.

1. These children are waiting in a line. Start at the front, on the left.

   ABCDE

2. A is first. B is second. C is third. The order tells us where each child is.

   1st: A2nd: B3rd: C

3. Each dot stands for one object. A full row holds five; two full rows make ten.

   Third means one particular child. Three children means a group of three.

Worked example: A new example, together

Which word describes position 7 from the front?

1. Find the front of the queue. Count from there.

   Ordinal words name a position in an order, not the size of a group.

   ABCDEFGHIJ

2. Start counting at the stated end.

   ABCDEFGHIJ

   Which word describes position 7 from the front?

   seventh

3. Count each position once.

   ABCDEFGHIJ

4. Position 7 is seventh.

   ABCDEFGHIJ

5. Check the result against the question we started with.

   There are 6 positions before the seventh position.

   We found seventh. Ordinal words name a position in an order, not the size of a group.

   ABCDEFGHIJ

Common mistakes to discuss

• Counting from the wrong end. Position depends on the end we count from. The same child is third from the front and eighth from the back of ten, so the question must say which end.

Check your understanding

• Use ordinal numbers from first to tenth
• name a place in a queue
• check the answer against the original quantities and units

Explain your reasoning to an adult, then try a fresh question in the interactive lesson. A result from one attempt is not proof of lasting mastery.