Day 7 Advent Calendar: Estimating Cooking Times

Cooking Times for a Roast Using Ratio and Proportion: a Skill that Counts.

Toast to the roast, if it's on thyme...

Christmas Dinner often depends on timing the roast correctly.

Today’s task uses ratio and proportion to help you estimate a safe and accurate cooking time.

This is a Level 2 skill that applies directly to everyday life.

A turkey joint requires 20 minutes per 500g, plus an additional 90 minutes.

Your joint weighs 2.75 kg.

Step 1: 

Convert the weight into grams

2.75 kg = 2750 g

2.75 X 1,000 = 2,750

If you need any resources to build this skill, drop me an email or leave a comment for FREE RESOURCES on converting weights and measures and a conversion chart.

Step 2: 

Work out how many 500 g portions are in 2750 g

2750 ÷ 500 = 5.5 portions

Step 3: 

Multiply the number of portions by 20 minutes

5.5 × 20 = 110 minutes

This is the proportional stage of the calculation.

If you need any resources to build this skill, drop me an email or leave a comment for FREE RESOURCES WORKING WITH FORMULAE.

Step 4: 

Add the extra 90 minutes

110 + 90 = 200 minutes total

Convert into hours and minutes:

200 ÷ 60 = 3 hours with 20 minutes remainingTotal cooking time = 3 hours 20 minutes

If you need any resources to build this skill, drop me an email or leave a comment for FREE RESOURCES WORKING WITH TIME.

Skills that Count Check

Always convert weights first so your ratio method stays accurate.

Use 500 g as the “unit” for the calculation.

If the weight is not a neat multiple, decimals are fine as long as they are multiplied correctly.

The Skills that Count

Ratio and proportion help you plan timing for meals, budgets, travel and more.

Being able to scale quantities up or down builds confidence in everyday tasks, including Christmas cooking.