There are ten including the stuff smaller than that.
それ以下の大きさのものを含めると10個です。
は英語で
There are ten including the stuff smaller than that.
それ以下の大きさ = smaller than that
を含める = including
他
Including the stuff smaller than X/that there are ten (in all/total).
There are ten in all including the stuff smaller than that/X.
アメリカ合衆国 
