To find the number of square units in an area, you can multiply the length by the width of the area. In this case, the office is 13 units long and 9 units wide, so the total number of square units in the office would be:
13 units * 9 units = 117 square units
This means that the office has an area of 117 square units. This is calculated by multiplying the length of the office (13 units) by the width of the office (9 units). It's worth mentioning that square units is a dimensionless unit which means it doesn't have any specific unit of measurement as it could be in meter square or feet square depending on what unit you are using for length and width.