What Are Missing Numbers?

• Missing numbers are the blank spaces in a counting line where a number should be.
• Every number has its own special home in a sequence, and they must stay in the correct order.
• When a number is missing, the "number chain" is broken, and we need to find the right number to fix it.

How to Find a Missing Number To find the hidden number, we look at the numbers nearby. These are called neighbors.

• The After Rule: Look at the number right before the blank space. Count one step forward to find the next number.
• The Before Rule: Look at the number right after the blank space. Think about what number you say just before it when you count.
• The In-Between Rule: When there is a gap between two numbers, the missing number is the one that joins them together.

Where Do Numbers Hide? A number can be missing at the start, in the middle, or at the end of a line.

• Missing at the Start: ___, 2, 3 (The number 1 is missing).
• Missing in the Middle: 7, ___, 9 (The number 8 is missing).
• Missing at the End: 4, 5, ___ (The number 6 is missing).

The Counting Strategy

1. Put your finger on the very first number you see.
2. Start counting out loud: "One, two, three..."
3. When your finger touches the empty spot, the number you say out loud is the missing one.
4. Always read the whole line again after you find the number to make sure it sounds right.

Why Is This Important?

• It helps us remember the perfect order of numbers from 1 to 20 and beyond.
• It teaches us how to solve puzzles by looking for clues.
• It prepares us for adding and taking away numbers later on.

Lesson Summary

• Missing numbers are gaps in a counting pattern.
• We use the "Before" and "After" numbers to help us find the secret hidden number.
• A correct number line has no holes and follows a steady path.