Use the SUMIFS function to calculate the sum of all the values that meet a certain condition

The syntax is:

SUMIFS(column_to_add, column_to_search, condition)

SUMIFS(T1!A, T1!B, ">10")

will return the sum of all the values in column A of table T1 for which the value in table T1 column B is greater than 10
so for the table:

100 | 2 |

200 | 10 |

300 | 20 |

400 | 30 |

You can also have multiple conditions:

SUMIFS(T1!A, T1!B, ">10", T1!C, 3)

This will return sum of the values in column A for which the value in column B is greater than 10 and the value in column C is 3.
See the Tables page for more tips on how to work with tables.