Round a number down to the next multiple

=FLOOR(number, significance)

Count how many values are in a list of arguments

COUNTA(value1, [value2], ...)

Calculate the average of numbers in a range that meet specific criteria.

AVERAGEIF(range, criteria, [average_range])

Return the value or reference of specified cell(s)

Array form: =INDEX(array, row_num, [column_num])

Reference form: =INDEX(reference, row_num, [column_num], [area_num])

Remove irregular spacing from either end of or within a text string.

TRIM(text)

Return the relative position of a specified item in a range

=XMATCH(lookup_value, lookup_array, [match_mode], [search_mode])

Lookup values by column in a horizontal table or range

=HLOOKUP (lookup_value, table_array, row_index_num, [range_lookup])

Return the serial number of the current date

=TODAY()

Return TRUE or FALSE statements based on testing multiple logical conditions

=AND(logical1, [logical2], ...)

Count values in a range that meet a single criteria.

COUNTIF(range,criteria)

Replace one or many instances of specific text based on its content (not on its position).

SUBSTITUTE(text, old_text, new_text, [instance_num])

Return the reverse of TRUE or FALSE statements based on testing logical conditions

=NOT(logical)

Return the most common value in a data set

=MODE.SNGL(number1, [number2], ...)