Maths Revision Club

Here is a video on multiplying large numbers:

Multiplying Large Numbers using Traditional Methods from HS on Vimeo.

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What is 10% of 750?

Answer

To work out 10% of a number, just divide the number by 10

So 10 % of 750 is the same as

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Sometimes, it is better to see a concept explained in the form of an online maths video.  This is why we have been steadily adding maths worked example videos.  From adding of fractions to a quick overview of the mean, median and mode, we have a short video explaining it all.   Subscribe to Primemaths for less than the price of a single one-to-one tuition and watch these videos again and again.

Subtraction of Fractions from HS on Vimeo.

This book provides step-by-step maths worked examples covering all the topics needed to pass the 11+ Maths and Common Entrance Maths.  This book is suitable for students in the UK and International Students who also take the common entrance.

The guradian posted an interesting maths question from old 11+ maths exams:

“A man left home at 11.30 a.m. and cycled 5 miles to a railway station at the rate of 12 miles an hour. He waited 10 minutes at the station and then travelled by train a distance of 36 miles at the rate of 24 miles an hour. At what time did he reach his destination?”

What they did not show as usual was how to get to the answer.  So here goes:

Start – 11.30 a.m.

cycled to the station 5 miles at 12 miles in 1 hour, or 12 miles in 60 min.  This is the same as saying 1 mile in 60/12 minutes or 5 minutes. So he will do 5 miles in 25 minutes.

He waits for 10 minutes.

Travels by train 36 miles at 24 miles an hour or 24 miles in 60 minute .  This is the same as saying 2 miles in 5 minutes [dividing by 12 a common factor of 24 and 60] .   He will travel 36 miles [ 2 x 18 ] in 18 x 5 or 90 minues.

So the total time from the time he started would be 25 + 10 + 90 minutes or 125 minues.  1 hour is 60 minutes so 125 minutes is 2 hours and 5 minutes.

So he arrives at 11.30 —- 1 hour —> 12.30 —– 1 hour —-> 1.30 p.m — 5 minutes —> 1.35 p.m.

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A formula is another way of writing maths rules.  This is very useful when working out word problems.   A simple formula will be like:  Area = length x width.     Instead of length, in maths we can use l, w instead of width and A instead of area.   So we can then write

A = l x w.

Things to know about formulae (formulae is plural of formula).

1. A letter next to a number means they are multiplied together, i.e 6z means 6 x z
2. You can use any letter in formulae, a, b, n, z, x
3. Try not to use x as it can easily be confused with times or multiplication

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Seray has 4 sweets for every 1 sweet that Katie has. If Seray has 12 sweets, how many sweets does Katie have?

Answer:

The ratio of Seray to katies sweets is 4: 1. Write down pairs of numbers in this ratio (see the table)

Katie has 3 sweets.     Subscribe to increase your child’s chances.