# Primary School Arithmetic Is Essential To Pass Many GCSEs

Primary school arithmetic and maths is necessary to pass many GCSEs so it makes sense to master it otherwise it will be harder to learn new stuff for GCSEs

Here are some of them

• Accounting
• Biology
• Chemistry
• Computing
• Electronics
• Engineering
• Geology
• Home Economics
• Physics
• Statistics

You or your children may not be interested in these subjects but ignoring them makes it hard to get the expected 5 or more passes at GCSE.

Often the arithmetic which would have been all of a question at primary school is now a tool to help solve a problem.  Here is an example from chemistry

2 grams of calcium react with hydrogen chloride to give calcium chloride and hydrogen.

Ca + HCl -> CaCl2 + H2

What mass of hydrogen is produced?

You need to know

• A fact from chemistry – elements react in proportion to their atomic mass.
• And that the atomic mass of calcium is 40, the atomic mass of hydrogen is 1.
• And that we can ignore the chlorine (cl) as it’s not part of the answer.
• There is a small gotcha in that 1 calcium atom produces 2 hydrogen atoms, total atomic mass 2

So in this chemical reaction the mass of hydrogen produced will be 2/40 the mass of calcium.

2 grams x 2/40 = 1/10 gram hydrogen.

That’s it – pretty simple huh?

But if you can’t do or struggle with the arithmetic the question will be difficult and confusing.

If you become a chemist, or use chemistry in your job,  this sort of calculation will be part of your life.

It is an example of what I call scaling

If 2 ice creams cost £2.40 how much do 7 cost?

This sort of question is much beloved of television interviewers trying to show adults can’t do maths (by which they mean arithmetic) when they ambush shoppers and ask them to work out if multi-buy offers are value for money

Is it better to buy 2 cans of tomatoes for £3 or 4 for £3?

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