10.2 Special sequences — Practise

1. Write the first six square numbers.

Answer: $1,4,9,16,25,36$.

2. Work out $4^3$.

Answer: $64$.

3. Continue the triangular numbers $1,3,6,10,15,\ldots$ by two terms

Answer: $21,28$.

4. Continue $1,1,2,3,5,8,\ldots$ by two terms.

Answer: $13,21$.

5. Which is a square number: $30,36,40$? Give its square root.

Answer: $36=6^2$, so its square root is $6$.

6. Is 125 a cube number? State the whole number cubed.

Answer: Yes, $125=5^3$.

7. Work out the 6th triangular number.

Answer: $21$.

8. H The sequence is $1,4,9,16,25$. Give its name and the next t

Answer: Square numbers; $36$.