The first topic-- numbers

In this topic, we learned about factors and multiples, real numbers, and approximation and estimation.
I had a little problem with factors and multiples, as I was totally new to secondary one mathematics, and I could never make heads or tails of the confusing formulas to find the highest common factors and lowest common multiples that comes together with the seemingly endless powers of numbers. I flunked the first test I had, and it was because of this chapter.
The second chapter was on real numbers. This was a bit easier, as it mostly involved only finding out if one number was larger than the other and using the number line, which I was already quite familiar with in primary school. The parts on negative numbers were a bit harder, though, as I get confused occasionally and mix up negative numbers and positive numbers. There was also problems in the multiplication of negative numbers.
Approximation and estimation was a lot easier as compared to the other topics, as it mostly was about significant figures and decimals. Decimals and significant figures have a bit of difference, though. Decimals was about numbers behind the decimal point, but significant figures included the numbers before the decimal point as well.