noun
Used in demographic, census, and administrative contexts to refer to the count of households in a given area.
この町の世帯数は約1万です。
The number of households in this town is about 10,000.
国勢調査で世帯数が増えていることがわかった。
The census showed that the number of households is increasing.
世帯 means 'household' as a unit; 世帯数 is the numerical count of such units.
Compound of 世帯 (household) and 数 (number).