4. cd-am+c2=12×10−3×6+144=246. 11. When the quantities are alike, and their figns the fame, add the co-efficients, and to the fum prefix the fign, and annex the common letter or letters RULE II. When the quantities are alike, but their figns different, fubtract the leffer co-efficient from the greater; to their difference prefix the fign of the greater, and annex the common letter or letters. RULE III. When the quantities are unlike, write them one after another, with their proper figns and coefficients. -30+126 4ab In example 8th, the articles are to be arranged, so that like may stand under like. -3ab-2de-3c SUBTRACTION, RULE. 12. Change the figns of the fubtrahend, or suppose them changed, then proceed as in addition. The reafon of the foregoing rule is obvious; for if from any quantity a decrement be fubtracted, it is the fame as adding an equal increment. For example, If a man owe 100l. more than his ftock, the ftate of his affairs may be represented - 100l. or he is tool. worfe than nothing. But if another add 100l. to his flock, it is the fame thing as taking away his debt, for ineither of thefe cafes he will be worth nothing. MULTIPLICATION. RULE. 14-Multiply the coefficients, and to their product annex the letters of both factors together. If the figns of the factors be like, the fign of their product is +; but if the signs of the factors be unlike, the fign of the product is -. 15.-Powers of the fame root are multiplied by adding their 16. Radical quantities, under the like fign, are multiplied like others, and the product is placed under the same fign. 17.-If one or both factors be compound, multiply each term of the multiplicand by all the terms of the multiplier fuc cellively ceffively, and the fum of the particular products will be the pre 18. If one of the factors be a fraction, multiply its numerator by the other factor, and place the product over the given denominator. 19.-If both factors be fractions, multiply their numerators for the numerator of the product, and their denominators for the |