Types of gravel include: 1  Bank gravel: naturally deposited gravel intermixed with sand or clay found in and next to rivers and streams. 2  Bench gravel: a bed of gravel located on the side of a valley above the present stream bottom, indicating the former location of the stream bed when it was at a higher level.
1 is the sixth part of 6. 2 is two sixths, and also the third part, of 6. 3 is three sixths, and also half of 6. 4 is four sixths, and also two thirds, of 6. is the sixth part of 6. 2 is two sixths, and also the third part, of 6. 3 is three sixths, and also half of 6. 4 is four sixths, and also two thirds, of 6.
CT2 & 7 are also pretty independent of the others, so you can sit them whenever. I sat 1,2, and 7 together in my first sitting and that worked well. Then 3 & 6 together as 6 builds on 3, and can help you see how the 'theory' in 3 actually gets used. They are also the maths at the core of CT5 which I would sit next.