Key Concepts – Number – Addition and subtraction
- That place value is a really important concept which supports all other areas of mathematics and is based on unitizing, treating a group of things as one ‘unit'.
- That when we add we are putting groups together, therefore making our number bigger. This means the calculation is commutative and can be done in any order.
- That when we subtract we are removing, therefore making our number smaller.
- That subtraction is not commutative
- That one less than 10 is 9 and that one less than 100 is 99
- That when we add and subtract we don’t always have to count 1 at a time.
- That we don’t always have to start at 0 when we count on. We can count on because we are able to unitize the first number and count on from that ie 24 + 7
- That there are different words for add, subtract and equals, but they mean the same thing.
- That = can be at the start of a number sentence as well as the end.
- That = means to balance - equalise
- That is I know the answer to 1 addition, then I know the answer to another addition and 2 subtractions. - Inverse
- That knowledge of place value can support addition and subtraction by partitioning my number into tens and ones.
- That when crossing the tens boundary, the tens number is counted.
- That the symbol for addition is + and the symbol for subtraction is -
Key Vocabulary –
Add, Sum, Plus, Addition, Subtract, Minus, Take Away, Difference, Less than, More than, Number sentence, Calculation, Calculate, Ones, Tens, Digit, Place Value, Inverse, Commutative
Key Concepts – Geometry – Properties of shape
- Initially 2D shapes are defined by the number of sides and vertices they have and that there are regular and irregular shapes and that some 2D shapes have specific names dependent upon their properties.
- Pupils need a clear understanding that the number of sides, the number of vertices, symmetrical properties and size of angle are the properties of shape and how shapes are defined.
- 2D shapes are the faces of 3D shapes and that there are different 3D shapes that share the same 2D shapes.
Key Vocabulary –
Cube, Cuboid, Cylinder, Sphere, Square, Rectangle, Oblong, Circle, Shape, 2D, 3D, Properties, Sides, Edges, Corners, Face, Vertices, Symmetry
Common Misconceptions – Addition and subtraction
That when adding we start at a number and begin counting on from the next number. E.g. 4 + 3 we would could 1 jump as we reach 5
That when subtracting we start at a number and begin counting back from the next number. E.g. 6 – 2 we would could 1 jump as we reach 5
The idea of counting across tens boundaries. We count 9, 10, 11 therefore the 10 counts.
When subtracting you are unable to take a larger number from a smaller number and still get a positive number.
Common Misconception – Properties of shape
What do we mean by a 2D shape and a 3D shape – 2D just have length and width and 3D have length, width and breadth
That 2D shapes are only found as a face of a 3D shape. (You are not able to hold a 2D shape.)
That it doesn’t matter in what orientation a shape is, it is still that shape according to properties, ie a square or ‘upside down’ triangle (ie orientation doesn’t matter.