In this Course, you are going to learn the basic skills of arithmetic. I will introduce the modern digit system and compare with ancient tally system. You will learn how to use only 10 digits to make any number you want to make regardless the size of the numbers. You will know the difference between whole numbers and integers and apply them in difference situations. You will see and understand some basic arithmetic concepts such as: place value concept and inverse operation concept. You will understand that only the digits with the same value can be added or subtracted from each other. You will work with integers and whole numbers by ordering, adding, subtracting, multiplying and dividing them. You will see how the four basic operations are related to each other. You will find factors and multiples of numbers and identify common factors and common multiples of two numbers. You will then find the highest common factor (HCF) and the lowest common multiple (LCM) of two numbers. You will use prime factor tree to find prime factors of any numbers. Finally, prime factor tree and venn-diagrran will be used as basic tools to arrange and find the HCF and LCM of big numbers.