Year 4 Term 2

Key Concepts – Number – Addition and Subtraction

• That addition follows the commutative law so can therefore add numbers in any order
• That the inverse of addition is subtraction and that we can use this to help check our answers
• That the presentation of column addition and subtraction is essential to ensure the value of each digit is clear.
• That when you add one digit numbers together and they total a number greater than 10, you must exchange this into a ten and put it into the tens column. The same should happen if you have more than 10 tens or more than 10 hundreds.
• That children should be able to look at a calculation and make a decision as to how to calculate the answer – it needs to be efficient, effective and appropriate.
• Solving addition and subtraction two-step problems in context, deciding which operations and methods to use and why.
• It helps to estimate the answer by rounding to get a sense of the size of the answer.

Key Vocabulary – Addition and subtraction

Total

Equal to

Sum

Ones, tens, hundreds and thousands

Difference between

Take away

Minus

decrease

Addition

Plus

Make

Increase

Key Concepts – Perimeter

• That perimeter is used with 2D shapes
• That perimeter can be calculated by adding the length off all of the sides of a shape together.
• That perimeter allows you to calculate the total distance around the edge of a shape. We use the word circumference for circular shapes.
• That children understand the value of mm, cm and m and how to convert between these measurements
• That scaling is used where appropriate, for example measuring the perimeter of a football pitch, and therefore the measurements given are not always to scale

Key Vocabulary – Perimeter

Length

Width

Perimeter

Measure

Scale

Estimate

Centimetre

Millimetre

Metre

Common Misconceptions – Addition and Subtraction

That counting on can only help you work out the answer to addition calculations – when counting on is best to be used when subtracting numbers very close together.

That children do not understand the value of the whole number and rather see it as a series of singular numbers. This will cause problems when it comes to crossing boundaries.

That estimation should provide an approximate answer to a calculation and that it is correct to have an answer that is ‘nearly correct’.

Common Misconception – Perimeter

That children calculate perimeter by multiplying the length and width of a shape rather than adding the sides of the shape.

That children will confuse perimeter and area

That children will not check the unit of measure for each side and therefore have errors in calculating their answer.

That children will put the start of the ruler at the beginning of a side to measure it rather than putting 0 at the start of the line.