It is possible to add and subtract binary numbers in a similar way to base 10 numbers.

For example, 1 + 1 + 1 = 3 in base 10 becomes 1 + 1 + 1 = 11 in binary.

In the same way, 3 – 1 = 2 in base 10 becomes 11 – 1 = 10 in binary.

When you add and subtract binary numbers you will need to be careful when 'carrying' or 'borrowing' as these will take place more often.

Key Addition Results for Binary Numbers | |||||||

1 | + | 0 | = | 1 | |||

1 | + | 1 | = | 10 | |||

1 | + | 1 | + | 1 | = | 11 | |

Key Subtraction Results for Binary Numbers | |||||||

1 | – | 0 | = | 1 | |||

10 | – | 1 | = | 1 | |||

11 | – | 1 | = | 10 | |||

Calculate, using binary numbers:

(a) | 111 + 100 | |

(b) | 101 + 110 | |

(c) | 1111 + 111 |

Calculate the binary numbers:

(a) | 111 – 101 | |

(b) | 110 – 11 | |

(c) | 1100 – 101 |

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