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Refresh Your Basic Maths Mulitiplication and Division Skills

The ability to multiply and divide whole numbers are basic maths skills that you'll need when taking any numeracy test. Multiplying and dividing are really just repeated adding and subtracting: 4 + 4 is the same as 4 x 2. With dividing, you’re just finding out how many times you can take away one number from another before you get to zero.

Basic multiplication skills

The quick way to multiply is to chunk one of your numbers into smaller numbers – for example, if you have to multiply a number by 12, you can easily work out ten times the number and two times the number and add the answers together.

Here’s how you multiply two numbers together – for example, 45 x 17:

  1. Split the smaller number into tens and units (and hundreds if you need to – but that would be a pretty involved sum!) So, you’d split 17 up into 10 and 7.

  2. Split each of these into smaller chunks if you need to – ones, twos and fives work best. In the example 10 is already a nice number; 7 would become 5 and 2.

  3. Work out the big number multiplied by each of the chunks – in the example, you’d need 45 x 10 = 450, 45 x 5 = 225 and 45 x 2 = 90.

  4. Add these numbers together to get your final answer.

    image0.jpg

Basic division skills

The chunking method comprises three stages:

  1. Writing out highlights of one of your times tables. Don’t worry – you only have to do fairly easy multiplying here.

  2. Taking away numbers in groups until you get to zero. This bit is fairly easy, but can take some time.

  3. Adding up how many groups you took away. That’s your answer.

Here's how to solve 1098 / 9:

  1. The first thing to do is write out the highlights of your times table – in fact, just the ones that are fairly easy to work out.

    1. Work out two times the number you’re dividing by. Write down 2 x (your number) = (your answer) in the top left of your paper. In this example, you’d write down 2 x 9 = 18.

    2. Leave a gap below that, then work out ten times the number you’re dividing by and write down 10 x (your number) = (your answer). Here, you’d write down 10 x 9 = 90.

    3. Halve your answer from step 2 and write down 5 x (your number) = (your answer) between your answers for steps 1 and 2. For this case, you’d write 5 x 9 = 45.

    4. Now comes the clever bit! You know 2 x, 5 x and 10 x your number, so you can easily work out 20 x, 50 x and 100 x your number by simply adding a zero to the end of each. In the next column, you’d write down 20 x 9 = 180, 50 x 9 = 450 and 100 x 9 = 900.

    5. You can carry this on for 200 x, 500 x and 1000 x your number, and even higher numbers if you need to (don’t bother with numbers that are higher than the number you’re trying to divide!).

      image1.jpg
  2. Take away the groups.

    This middle step is the most time-consuming part of long division – the quicker you can do take-away sums, the more quickly you’ll be able to divide!

    image2.jpg
    1. Write down the number you’re trying to divide, 1098 in this case. Leave yourself plenty of space below and to the right.

    2. Find the biggest answer in your times table highlights that’s smaller or the same as your last answer; write the sum down to the right as well.

    3. Draw a line beneath your number from Step 2 and take the number away from the number above it.

    4. Repeat Steps 2 and 3 until your answer is zero!

    You may end up with your answer being the number you’re dividing by instead of zero. That’s okay: in that case, you just write the number and 1 x (the number) = (the number).

  3. Add up the groups.

    The last part is the easy bit! You simply pick out the first number in each of the times sums you wrote down (in this case, 100, 20 and 2), and add them up! So in this case, you get 122, which is 1098 / 9.

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