# Rainey's Improved Abacus; An Explanatory Treatise on the Theory and Practice of Arithmetic and Mensuration in Which the General Principles Involved in

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## Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1849 edition. Excerpt: ...the two lines; or whether among the extremes, or terms outside the two lines: if it fall among the inner terms, all of the inner terms must be placed on the left side of the vertical line, or line of ratio, on which the question is to be wrought: if among the outer terms, all of the outer terms must be placed on the left of this line. This is based on the principle of dividing by the mean or extreme, as the one or the other may be deficient, to ascertain the deficient term. Being thus stated, the question may be canceled as in other cases. Let us now recur to the first question: If 4 men in 8 days mow 12 acres, how many acres will 8 men mow in 16 days? and state it thus, -j gi0 Here we inclose the mean terms en g 2g tirely, which are 12, 8, 16, that they!! may bo clearly distinguished from the extreme, which are 4 and 8. The blank falling on the outside, the outer terms become the divisors, and the inner terms the dividend, and are placed on the right; thus, Y Y j Eight equals 8; 4 into 12, 3 times, and 3x16=48 acres, the answer. 48 acres. I We now resume the second question, which will prove this correct. If 4 men in 8 days mow 12 acres of grass, in how many days will 8 men mow 48 acres? Four and 8 are the causes, in the supposition, and 12 the effect; 8 and blank the causes, in the demand, and 48 acres the effect. After stating the question, thus, it is seen that the blank is among the means; hence, the means, 12 and 8, be come the divisors, and are accordingly placed on the left; while 4, 8, and 48, the extremes, are placed on the right of the line, where the dividend is always placed; thus, Days being the deficient term, the answer is 16 days. Again: If 4 men in 8 days mow 12 acres, how many men will be required to mow 48 acres in 16..show more

## Product details

• Paperback | 70 pages
• 189 x 246 x 4mm | 141g
• Miami Fl, United States
• English
• black & white illustrations
• 1236523512
• 9781236523518