October 14, 2014 § Leave a comment
It’s chocolate week this week – a time when you actually have an excuse for indulging!
And at the same time, Ireland are enjoying maths week . . . maybe a less pleasurable experience for most people!
So, let’s mix it together and take a look at the importance of maths in chocolate.
The percentages on the front of chocolate bars refer to weight: they refer to how much of the total weight of the chocolate bar is made up of actual cocoa bean products. By cocoa bean products, we mean cocoa butter and cocoa solids. So, “70% cocoa” means that 70% of the weight of the chocolate bar is made up of cocoa bean products, while the rest is mostly sugar (yikes!) with a touch of vanilla, lecithin (this makes it smooth and creamy) and milk solids if it’s milk chocolate or white chocolate.
A typical cocoa bean is made up of 54 percent cocoa butter and 46 percent cocoa solids (the solids are often ground down and used to make cocoa powder). Different amounts of the cocoa butter and cocoa solids will be used depending on what type of chocolate you eat. White chocolate, for instance, contains cocoa butter without the cocoa solids.
So, as you sit back and tuck in to a chocolate-y treat, spare a thought for those clever chocolatiers who have mixed the right percentages together to make it!
November 1, 2010 § 2 Comments
Percentages are another tricky subject that often confuses children at school! Just like fractions, there is so much to learn about working with percentages: finding the percentage of a quantity, changing decimals and fractions into percentages and vice versa, not to mention finding one quantity as a percentage of another! Percentages, though, are a vital tool for later life. Many of us use percentages in our day-to-day life without even thinking about it, simply by working out VAT!
So, what is a percentage? A percentage is a way of expressing a number as a portion of 100.
How do we use percentages? We say that 100 is the whole of something and the percentage is the amount of it we are using. (For example, we say that a whole cake is 100%. If I eat half of that cake, we are left with 50%.)
Very often, it is much easier to use fractions, but when it comes to really complicated fractions, it is sometimes just easier to say 79% instead of 79 hundredths! Again, percentages is one of those topics that a child can often fall behind in because they have not understood a certain part of it. That’s why it’s always best to start at the beginning if your child is ever going to be confident about using percentages in the 11+ exams or at any stage in their school life. Don’t forget that percentages will take up a few questions in GCSE mathematics!
Do I know what a percentage is?
Can I change a fraction into a percentage?
Can I change a decimal into a percentage?
Can I find the percentage of a quantity?
Do I know the simpler methods for using percentages like 25% and 50%?
If your child can answer “yes” to all those questions, they are a percentages maths star! If there are a few “no”s, try Maths Star’s 11+ Percentages page.