Build the Engine.

Third class. Sometimes a number arrives as text. We convert it first, then calculate.

int("25") creates a whole number, while float("1.8") creates a decimal. Converted values can take part in +, -, *, /, and **. Health Engine uses BMI as the connecting example.

BMI (Body Mass Index) is a simple formula: weight divided by height squared. In Python, exponentiation is **. So height ** 2 is height×height. The full expression: weight / height ** 2.

Important: operator order. ** runs before /. You do not need parentheses for this formula, but if you get confused, weight / (height ** 2) is the same and easier to read.

With our lesson data — height 1.8 m and weight 75.0 kg — BMI is about 23.15. That sits in a “normal” range, but classification comes next class. Today we only compute and show the number.

Mini example:

h = 1.8
w = 75.0
value = w / h ** 2
print(round(value, 2))

round(..., 2) rounds to two digits after the decimal point — handy for reading in the console.

Common mistake: writing height ** 2 as height * 2 (doubling, not squaring). Or using text values without int/float — then division breaks.