# 9.3.1 Math in Cooking The calculator can be accessed on the left-hand side bar under Toolkit.

The time to cook a fresh chicken depends on its mass, commonly called weight in everyday language, as given by the following formula:

Roughly how long will a chicken with a mass of 2.2 kg take to cook?

To use the formula, you need to substitute the mass of the chicken into the right side of the equation and then work out the resulting calculation. However, the formula asks for the mass in grams, so the first step is to convert 2.2 kilograms (kg) into grams (g).

Since there are 1000 g in 1 kg, .

Substituting 2200 for the mass in grams gives: .

Carrying out the multiplication and division first gives (remember PEMDAS!): .

So, the cooking time would be about 125 minutes, or 2 hours and 5 minutes. If you prefer, you can use a calculator, but remember to make an estimate first so that you may check that your answer is reasonable. ## Activity: A Smaller Bird

How long would it take to cook a chicken with a mass of 1.6 kg? 