Year 4 Investigate and Make Conjectures in Maths

This week in Year 4, we have been completing investigations and making conjectures in Maths. We learned that a conjecture is a mathematical statement that is based on evidence and believed to be true.

We began the lesson looking at an image of the numbers one to twenty with a circle of colour(s) surrounding each number. For example, the number two only had an orange circle around it but the number four had two orange sections in the circle. Then, we used these colours to begin to make conjectures and spot patterns. After exploring the numbers for a little while, we discovered that because the number two had an orange circle around it, all multiples of two had orange in their circle. From this, we were able to make more conjectures and even predict what the next set of numbers would look like.

Exploring the numbers up to 60 allowed us to see whether or not we could prove our conjectures were accurate. In the end, we all reached the conclusion that we needed to multiply all of the colours in each circle to produce the number in the centre. We also made these conclusions from looking at all of the numbers:

Annabelle: We found that 9, 18 and 36 have green in them because they are multiples of 3. All multiples of 3 have green in them.

Harvey: We can make 33 out of half red and half green because 11 (red) x 3 (green) = 33.

Elodie: All even numbers have some orange in them because they are in our 2 times table and the number 2 is orange.

Elsa: Numbers that are in more than one times table have more than one colour.

Max: All prime numbers only have 1 colour because they can only be divided by itself and one.

Isaac: All prime numbers are odd except the number 2.

Henry and Theo: 100 will have 2 blue sections (each representing 5) and 2 orange sections (each representing 2) because 5 x 5 = 25 and 25 x 4 = 100.