The paper on arithmetic in second grade examinations usually contains one, sometimes two, problems in common or decimal fractions. These are no more difficult to solve when one understands the rules governing them, than any simple test in addition, division, etc. In whole numbers, as 57, 563, 4278, the various units increase on a scale of ten to the left (or decrease on the same scale of ten to the right). Thus in the last number we say 8 units, 7 tens, 2 hundreds, and 4 thousands or four thousand two hundred seventy-eight. Decimals also decrease on a scale of ten to the right (or increase on the same scale of ten to the left). In writing decimals, we first write the decimal point, which is the same mark we use at the close of a sentence and is called a period. Then the first figure to the right is called “tenths” and is written thus .6, meaning six tenths. The second figure stands for hundredths as .06, six hundredths; .006 for six thousandths; .0006 for six ten-thousandths; .00006 for six hundred-thousandths; .000006 for six millionths, etc. When a whole number, previously mentioned, and decimals are written together as 47.328, it is called a mixed number. The only distinction between reading whole numbers and decimals is made by adding this to the ending of decimals, and the denomination of the right-hand figure must be expressed to give the proper value to decimal parts. For instance, .12, is twelve hundredths; .007, is seven thousandths; .062, is sixty-two thousandths; .201, is two hundred one thousandths; .5562, is five thousand five hundred sixty-two ten-thousandths; .24371, is twenty-four thousand three hundred seventy-one hundred-thousandths; .893254, is eight hundred ninety-three thousand two hundred fifty-four millionths, etc. Remember that in decimals the first figure stands for, tenths; the second, hundredths; the third, thousandths; the fourth, ten-thousandths; the fifth, hundred-thousandths; the sixth, millionths, and that in reading decimals we add the denomination of the right-hand figure. When reading a mixed number the word “=and=” is used, and then only, to indicate the decimal point. Thus 45.304 should be read forty-five AND three hundred four thousandths. Addition and subtraction of decimals differ from similar operations of whole numbers only in the placing of the figures. In whole numbers units come under units, tens under tens, etc. To illustrate: What is the sum of 260, 4398, 305, 2, 29? The figures are placed thus: 260 4,398 305 2 29 ----- 4,994 Now let us take the same figures expressed decimally: .260, .4398, .305, .2, .29. .260 .4398 .305 .2 .29 ------ 1.4948 In subtraction of whole numbers or decimals the figures are placed as in addition. Examples--Subtract .204 from .4723. .4723 .204 ----- .2683 Subtract 5.346 from .937. 5.346 .937 ----- 4.409