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SOLID, OR CUBIC MEASURE S. yd. S. ft. S. in. C. S. ft.
Cord ft. 4 26 1000 10 120 1 10 1541 8 100 10 4 0 20 80
2 80 12 : 10 17 11 0 119 8 6 8 25 59126 15 3 26 18 963 35 41 50 5
83. If we wish to subtract £15 13s. 10d. from £20 5s. 8d., we proceed as follows: OPERATION. 1 We place the numbers of the subtrahend £ $. d.
directly under the numbers of the same 20 5 8 denomination in the minuend, and draw a 15 13 10 line underneath. Commencing with the 4 11 10 pence, we see that we cannot subtract 10d.
from 8d. ; we therefore increase the 8d. by 12d. making 20d.; then subtracting 10d. from the 200., we have the difference 10d., which we write under the column of pence. Having added 12d. to the minuend, we must equally increase the subtrahend, which we do by
adding ls. (the same as the 12d.,) to the 13s., makirig 14s. T'his cannot be subtracted from 5s.; we therefore increase the 5s. by 20s., making 25s. Now, subtracting 14s. from 25s. we have 11s., which we write under the column of shillings. Before subtracting the pounds, we add £1 to £15 to compensate for the 20s. added to the 5s., and ther. say £16 from £20 leaves £4.
Note.-It will be seen that this process is similar to that in che “ shorter and more practical” example of simple subtraction, (ART. 12.) But the preceding subtraction might be also performed as in the second example of simple subtraction.
Hence, we have this general
1. Place the less number under the greater, so that the same denominations may stand under each other; draw a line below them.
II. Begin at the right, and subtract each number in the lower line from the one directly above it, and set the renainder below.
III. If any number in the lower line is greater than the one above it, add so many to the upper number as make one of the next higher denomination; then subtract the lower number from the upper one thus increased, and set down the remainder. Carry 1, expressing the increase of the upper ine, to the next number in the lower line ; after which subIract this number from the one above it, as before ; and thus proceed till all the numbers are subtracted.
PROOF. If the work be right, the difference added to the subtrahend will equal the minuend; as in simple subtraction.