1 - The Basic Skills

Abstract

This chapter focuses on the number system. The number system is a decimal system because it is based on 10. Any number can be written using the proper choice and combination of 10 symbols—0 through 9. The decimal system is a place value system. This means that the value of each digit depends in part on its position within the number. On moving to the left in a decimal number, each place is worth 10 times the previous place; on moving to the right, each place is worth one-tenth of the previous place. A rounding variation that is found in other studies is the computer rule, which can avoid errors in rounding large series of numbers. By means of this rule, some numbers may become larger while others become smaller. The correct alignment of numbers around the decimal point is essential in successful addition. To accomplish this, the numbers must be put in a column by lining up the decimal points and by filling in zeroes for any numbers with fewer decimal digits than the longest number.