- Define and explain Counting to 100 in your own words
- Use key terms such as Estimate accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
This lesson focuses on Counting to 100: count on and back in ones and tens up to 100.
Count on and back in ones and tens up to 100.
Key ideas
One-to-one counting
Touch or point to each object once and say one number name each time. That way no object is missed and none is counted twice.
Counting on
Instead of starting at 1 each time, keep counting from a number you already know. This makes adding and checking totals much faster.
Key term — Estimate: A sensible guess of how many there are, found by counting part of a group and scaling up.
A packet has 31 biscuits. You eat 1. How many are left?
30 — counting back one from 31 gives 30.
Answer: 30 — counting back one from 31 gives 30.
- Counting an object twice Point to each object once as you count it, moving counted objects aside if it helps.
- Thinking 9 is bigger than 11 Compare by seeing which comes later in the count, not by how big the digit looks.
Practice
70, 60, 50, 40, 30.
29, because 29 comes after 25 when counting.
14, 15, 16, 17, 18, 19, 20.
Quick check
Which of these best defines "Estimate"?
Write the numbers 8, 3, 11, 5 from smallest to largest.
- Counting to 100: count on and back in ones and tens up to 100.
- One-to-one counting: Touch or point to each object once and say one number name each time.
- Number: A word or symbol that tells you how many there are, such as 7.
- Watch out for: counting an object twice