1.2⋅15.5

Multiply 5 by 2. Place the ones digit (0) in the result line and carry the tens digit (1). There is one result line for each digit in 15.5.

1 | |||

1 | .2 | ||

⨯ | 1 | 5 | .5 |

0 |

Multiply 5 by 1 and add the carried 1. Place the result in the next column in the result line. There is one result line for each digit in 15.5.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 |

Multiply 5 by 2. Place the ones digit (0) in the result line and carry the tens digit (1). There is one result line for each digit in 15.5.

1 | |||

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

0 |

Multiply 5 by 1 and add the carried 1. Place the result in the next column in the result line. There is one result line for each digit in 15.5.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 |

Multiply 1 by 2. Place the result in the next column in the result line. There is one result line for each digit in 15.5.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

2 |

Multiply 1 by 1. Place the result in the next column in the result line. There is one result line for each digit in 15.5.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 |

Add the numbers in each column. In this case, add 0+0+0, then place the 0 in the result line.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 | ||

0 |

Add the numbers in each column. In this case, add 6+0+0, then place the 6 in the result line.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 | ||

6 | 0 |

Add the numbers in each column. In this case, add 0+6+2, then place the 8 in the result line.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 | ||

8 | 6 | 0 |

Add the numbers in each column. In this case, add 0+0+1, then place the 1 in the result line.

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 | ||

1 | 8 | 6 | 0 |

1 | .2 | ||

⨯ | 1 | 5 | .5 |

6 | 0 | ||

6 | 0 | ||

1 | 2 | ||

1 | 8 | 6 | 0 |

To find the number of decimal places needed in the answer, add the number of decimal places in the multiplier and multiplicand. In this case, there is a total of 2, so the answer must have 2 decimal places as well.

18.6

Evaluate 1.2*15.5