To count the items, call each one a number in order from 1 to 10:

1_2_3_4_5_6_7_8_9_10

Also, you can use this number line to identify the missing digits.

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What is a rule? It is a kind of restriction that sets the order.

Which rules do you know? Traffic rules help people to be safe while on the road. Pedestrians cross the road at the green light in a specially designated place. Cars stop at this moment. If you break this rule and go at a red light, there will be an accident.

The ethics rules are essential for establishing good relations between people. They help to resolve arguments and conflicts.

The scientific world also has its own rules. A sequence of numbers is not a random set but a pattern. It means that the numbers are arranged according to certain rules. These rules help to establish relationships between numbers and make calculations. Let's remember them:

1. A number line is a sequence in which each next number is greater than the previous by one. It means that to get the next number, you need to add 1 to the previous digit.

2. The numbers increase from left to right and decrease from right to left.

3. The order of the numbers never changes. Each digit has nearby numbers to the right and the left: there is always 4 to the left of 5, and 6 to the right of it.

4. Calculating objects, we call them numbers in order from 1 to 10. The last number that we say when counting objects denotes their total number.

5. When counting, you need to count each object only once.

Knowing these rules, complete the following task.

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