When thinking mathematically, most people think in proportions. For example, if someone is baking cookies and they want to make a double batch, they intuitively know they need to double the amount of ingredients.
If someone was told a 100-horsepower (hp) engine could make a certain car go 100 mph at full throttle, and was then asked how fast a 200-hp engine would make the same car go, he’s likely to answer 200 mph.