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43. Definitions and Explanations. (a.) COMPOUND SUBTRACTION is the subtraction of compound numbers.
(b.) It involves the same principles that simple subtraction
(d.) When reductions are made, the remainder can often be found most easily by subtracting from the reduced unit, and adding the remainder thus obtained to the minuend figure.
ILLUSTRATION. — In the above example, by the first reduction, we have 1 dwt. = 24 gr.; and 21 gr. from 24 gr. leave 3 gr. to be added to the 14 gr., giving 17 gr.
By the second reduction, we have 1 oz. = 20 dwt.; and 18 dwt. from 20 dwt. leave 2 dwt., to which adding the 15 dwt. (left after the former reduction), gives 17 dwt., etc. etc.
(e.) Another method, which is often found convenient, is to subtract as much of each denomination of the subtrahend as possible, from the corresponding denomination of the minuend, and then subtract the rest from the reduced unit.
ILLUSTRATION. -- In the above example, we can subtract 14 of the 21 gr. from the 14 gr. of the minuend, and then the remaining 7 gr. from the 1 dwt. or 24 gr.
(a.) If, in Long or Square Measure, it is necessary to reduce a rod to yards, the reduction should be made, and the } or of a yard reduced to feet and inches, before commencing the subtraction.“
1. A man bought 17 cwt. 2 qr. 13 lb. of sugar, and sold 14 cwt. 2 qr. 21 lb. How much had he left ?
2. An English' merchant bought goods for £327 14s. 6d., and sold them for £596 10s. What was his gain ?
3. My wood-lot is 32 rd. long, and 27 rd. 2 yd. 2 ft. wide. What is the difference between its length and its breadth ?
4. I bought a bar of silver weighing 7 lb., and made 5 lb. 7 oz. 5 dwt. 14 gr. of it into tea-spoons, and the rest into salt-spoons. How much did I make into salt-spoons ? · 5. A farmer, carrying a load of hay to market, found that the hay and the cart together weighed 2 T. 7 cwt. 3 qr. 16 lb., and the cart alone weighed 18 cwt. 1 qr. 22 lb. What was the weight of the hay?
6. A trader purchased some sugar for $327.13, some molasses for $125.50, some flour for $520.62, some butter for $132.28, and some cheese for $86.72, giving in payment a lot of cloth worth $625.47, and the rest in money. How much money did he pay?