How to help your child with mental maths – Part 1

mental maths key stage 2

In the new Year 6 SATS paper, children now have an arithmetic test which comprises of around 36 questions to be answered in 30 minutes. Children will start to practise these tests throughout Key Stage 2. The tests can be answered using written methods or mental methods. Some questions will have to be answered using written methods as the numbers will be too large or complicated for children to work out mentally. However, there will be lot of questions which can be answered mentally, saving valuable time in the test and allowing more questions to be answered. In this blog post, we will look at some of the mental maths methods your child can use in the tests.

The first most important thing which will make a huge difference to your child’s ability to answer mental maths questions at speed is confidently knowing their times tables! See my previous blog posts on learning times tables and making times table learning fun to help with this.

Adding and subtracting 100s (Years 3, 4, 5 and 6)

Questions such as 309 + 100, 540 – 500 and 182 – 100 can be answered quickly without a written method. Ask your child to identify which digit is in the hundreds column (use the place value chart below to help) and then add or subtract the number of hundreds.

e.g. 309 + 100 = the digit 3 is in the hundreds column so add on 100 to 300 – all other columns stay the same so the answer is 409.

e.g. 540 – 500 = the digit 5 is in the hundreds column so take 500 away from 500 (leaving no hundreds) – all other columns stay the same so the answer is 40.

e.g. 182 – 100 = the digit 1 is in the hundreds column so take 100 away from 100 (leaving no hundreds) – all other columns stay the same so the answer is 82.

Th (Thousands) H (Hundreds) T (Tens) O (Ones)

Have a go at these with your child: 207 + 100 (307), 405 + 200 (605), 306 – 100 (206) , 520 – 500 (20).

Please note: In Year 3, children will begin by adding and subtracting ones and tens in 3 digit numbers (e.g. 327 – 1, 450 + 10) before moving onto adding and subtracting hundreds. The same method can be used as above for ones (by identifying the number in the ones column) and tens (by identifying the number in the tens column) and then adding or subtracting the given number.

Adding and subtracting 1000s (Year 4, 5 and 6)

The same principle applies as explained above except this time children need to identify the number in the thousands column.

e.g. 276 + 1000 = there are no thousands in this number so you add 1000 to make 1276.

e.g. 1728 – 1000 = the digit 1 is in the thousands column so you take 1000 away from 1000 (leaving no thousands) so the answer is 728 as the other columns stay the same.

Have a go at these with your child: 367 + 1000 (1367), 1894 + 1000 (2894), 3456 – 1000 (2456), 1276 – 1000 (276).

Adding and subtracting fractions (Years 3, 4, 5 and 6)

The top of a fraction is called the numerator and the bottom of the fraction is called the denominator. This is the method to add and subtract fractions when the denominators are the same.

Adding fractions:

With the same denominator: add the numerators only. The denominator stays the same.

e.g. 2/4 + 1/4 = 3/4

Subtracting fractions:

With the same denominator: subtract the numerators only. The denominator stays the same.

e.g. 3/4 – 1/4 = 2/4

Have a go at these with your child: 2/6 + 3/6 =5/6  2/8 + 4/8 =6/8

4/8 – 2/8 =2/8          5/10 – 3/10 = 2/10

 

For more information on private tutoring to help your child in Numeracy and/or Literacy, please see the Private Tutoring page.

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