Arithmetic for the Grandchildren

The numbers between the vertical lines are of two kinds. The ones that are not set equal to other numbers are called **prime numbers**. They are printed in bold. The others are each set equal to two other numbers multiplied by each other. The x indicates multiplication. A number set equal to the multiplication of numbers is called a **product**.

The listing shows that 54 is the product of 6 and 9 (54 = 6 x 9). There is more than one way to get 54. It is also equal to 3 x 18. These are the products that you should learn first. Learning the ones at the start of the list before learning the later ones is also a good idea, because knowing them allows you to understand the products that come later.

**2** | **3** | 4 = 2 x 2 | **5** | 6 = 2 x 3 | **7** | 8 = 2 x 4 | 9 = 3 x 3 | 10 = 2 x 5 | **11** | 12 = 2 x 6| **13** | 14 = 2 x 7

15 = 3 x 5 | 16 = 2 x 8 |**17** | 18 = 2 x 9 | **19** | 20 = 2 x 10 | 21 = 3 x 7 | 22 = 2 x 11 | **23** | 24 = 2 x 12 |

25 = 5 x 5 | 26 = 2 x 13 | 27 = 3 x 9 | 28 = 2 x 14 |**29** | 30 = 2 x 15 | **31** | 32 = 2 x 16 | 33 = 3 x 11 |

34 = 2 = 17 | 35 = 5 x 7 | 36 = 4 x 9 |**37** | 38 = 2 x 19 | 39 = 3 x 13 | 40 = 4 x 10 | **41** | 42 = 6 x 7 |

**43** | 44 = 4 x 11| 45 = 5 x 9 | 46 = 2 x 23 | **47** | 48 = 6 x 8 | 49 = 7 x 7 | 50 = 5 x 10 | 51 = 3 x 17 |

52 = 4 x 13 |**53** | 54 = 6 x 9 | 55 = 5 x 11 | 56 = 7 x 8 | 57 = 3 x 19 | 58 = 2 x 29 | **59** | 60 = 6 x 10 |

**61** | 62 = 2 x 31 | 63 = 7 x 9 | 64 = 8 x 8 | 65 = 5 x 13 | 66 = 6 x 11 | **67** | 68 = 4 x 17 | 69 = 3 x 23 |

70 = 7 x 10 |**71** | 72 =8 x 9 | **73** | 74 = 2 x 37 | 75 = 3 x 25 | 76 = 4 x 19 | 77 = 7 x 11 |78 = 6 x 13 |

**79** | 80 = 8 x 10 | 81 = 9 x 9 | 82 = 2 x 41 | **83** | 84 = 4 x 21 | 85 = 5 x 17 | 86 = 2 x 43 | 87 = 3 x 29 |

88 = 8 x 11 |**89** | 90 = 9 x 10 | 91 = 7 x 13 | 92 = 4 x 23 | 93 = 3 x 31 | 94 = 2 x 47 | 95 = 5 x 19 |

96 = 3 x 32 |**97** | 98 = 2 x 49 | 99 = 9 x 11 | 100 = 10 x 10 |

Counting by two (2, 4 6, 8, 10) is not the only way to count by steps. Once you get familiar with the numbers, you might try counting by eleven, of any other number. These exercises will give you a fast way to become skilled in arithmetic.

The listing shows that 54 is the product of 6 and 9 (54 = 6 x 9). There is more than one way to get 54. It is also equal to 3 x 18. These are the products that you should learn first. Learning the ones at the start of the list before learning the later ones is also a good idea, because knowing them allows you to understand the products that come later.

15 = 3 x 5 | 16 = 2 x 8 |

25 = 5 x 5 | 26 = 2 x 13 | 27 = 3 x 9 | 28 = 2 x 14 |

34 = 2 = 17 | 35 = 5 x 7 | 36 = 4 x 9 |

52 = 4 x 13 |

70 = 7 x 10 |

88 = 8 x 11 |

96 = 3 x 32 |

Counting by two (2, 4 6, 8, 10) is not the only way to count by steps. Once you get familiar with the numbers, you might try counting by eleven, of any other number. These exercises will give you a fast way to become skilled in arithmetic.