These are the answers:

1.  151 + 464 = 615
2. q = 48
3. 4/6 x 3/5 = 12/30 = 6/15 = 2/5
4. a=160 degrees   b= 20 degrees
5. Tracey decided to walk because/as/since it was a lovely day.
6. The detective discovered the vital clues.
7. worthless and valuable
8. Jim is learning French at school. He is planning to ski in the Alps in the spring.