You put in a variable to substitute the unknown number.
The Cascades rain shadow can be described as such: ocean-influenced moist air masses are forced to rise when they meet the tall moun- tains. The rising air cools, condenses, and the moisture falls as precipitation. On the leeward (dry) side of the mountain, the now dry air warms and sinks.
<span>Grams of solute per 100 grams of water</span>