**Decimal Number System**

The decimal number system is a place system. The right most place is the ones place. As we move from right to left, each place is 10 times the previous place.

Place: | 1000 |
100 |
10 |
1 |

Digit: |
1 |
0 |
4 |
3 |

Value: |
1x1000 |
0x100 |
4x10 |
3x1 |

The number 1043 means 1 group of 1000, 0 groups of 100, 4 groups of 10 and 3 groups of 1.

You cannot leave out the 0 in the 100s place. 1043 is not the same as 143.

The place values can also be written as powers of 10. The two rows in the table below have the same values.

Place: | 1000 |
100 |
10 |
1 |

Power: |
10 |
10 |
10 |
10 |

In the decimal system, there are 10 digits 0, 1, ,2, 3, 4, 5, 6, 7, 8, 9. There can only be 1 digit in a place. You cannot put a 12 in the tens place. For 12 groups of 10, You would need to put a 2 in the 10s place, and a 1 in the hundreds place: 120. Sometimes we called that carrying: We carry a 1 to the hundreds place.