**Task Name : **Adding and Subtracting Negative Number Stories |
**Task Level : **H (Year 7) |

**Semester : **1 |
**Topic :** Directed Numbers |
**VC Strand : **Number and Place Value |

**Web Address : **http://maths.crusoecollege.vic.edu.au/npvH |

**Equipment Needed : **Poster Paper |

**Victorian Curriculum outcome : **Compare, order, add and subtract integers |

**Task description : **Students create eight stories that describe addition and subtraction of positive and negative numbers. Two should describe the addition of positive numbers; two should describe the subtraction of positive numbers; two should describe the addition of negative numbers; and two should describe the subtraction of negative numbers. Each story should contain: the written story; a picture accompanying the story; a number line describing the story; and an algorithm describing the story. |

**Assessment options : **Photograph of poster; digital image. |

**Teacher notes : **Money is a good way to describe these processes. If I have $5 and I gain $10, the algorithm is ^{+}5 + ^{+}10 = ^{+}15 . However, if I have $5 and then gain a bill for $10, this can be thought of as “negative money”, and so the algorithm is ^{+}5 + ^{–}10 = ^{–}5. Using this analogy, it is easy to see why if I lose a bill (perhaps the issuer recognises that it is a mistake and takes it back), then the algorithm is ^{+}5 – ^{–}10 = ^{+}15… students can see that losing a bill means that you are better off financially. |