This picture is taken from the Problem Pictures Themes resource of photographs with activities for mathematics teaching.
If you purchase this resource the photographs are available in higher resolution and there are additional pages containing hints and solutions.
How many squares does this chocolate bar have? To answer this question, it may help to measure the photograph with a ruler.
The whole bar weighs 100 grams. What does one square weigh? A recipe uses 28 grams of chocolate. How many squares is this?