A parent's guide to subtraction methods taught in Guernsey Primary Schools

One of the trickier concepts in early maths learning is that of subtraction. As children in Guernsey preschools and Reception begin learning to count in a linear way, starting from zero and counting up, the model of numbers getting bigger is better embedded in children's understanding than that of counting backwards. Although teachers and maths tutors in Guernsey dedicate plenty of learning and teaching time to this, it is still a concept that many children find challenging.

As many parents will recognise, the methods taught in Guernsey primary schools are quite different from what they learned themselves in Key Stage 2. Your child's teacher or maths tutor should be able to advise you as to which stage of calculation your child is currently using.

Prior learning

In Reception and Key Stage One, children will have practiced lots of counting both forwards and backwards, been taught the basics of place value, and used a range of maths equipment such as ten frames, numicon, counters, and Base 10 or Dienes equipment.

Numberlines

Lots of the fundamentals of using a numberline for subtraction are similar to the addition method, with the difference being that jumps go backwards, under the line. It is important that your child has a firm understanding of place value before starting to use methods that rely on partitioning a two-digit number into tens and ones. Many teachers and maths tutors in Guernsey like to continue using a numberline method until this knowledge is fully embedded.

Partitioning method

Much like the addition partitioning method, the subtraction partitioning method relies on children's understanding of place value, and being able to partition a two digit number into tens and ones. One of the hardest concepts for children to grasp – and one which our maths tutors in Guernsey spend a lot of time working on – is that of 'exchanging' or 'repartitioning', which happens when there aren't enough of a number to subtract while staying in positive numbers. This is a method which many children need extra time and tutoring to master, including situations where zero is used as a placeholder and where more than one exchange must be made.

How else can subtraction be shown?

The Singapore Bar Model and Part/Part whole models are used in Guernsey schools to help children visualise what a particular problem is asking learners to do, giving a visual representation of what is being asked without solving the arithmetic itself.

What's the take away?

Ultimately, the methods taught progressively to children before they attempt formal written methods are designed to carefully develop a child's understanding. Guernsey's teachers and maths tutors are experienced in making sure that children have the necessary skills and confidence before moving on to the next stage. If you think this is an area of maths where your child needs more support, please get in touch to see how one of our Guernsey maths tutors can help.