Tochio's Computation on the Soroban/Subtraction

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SUBTRACTION.

TABLE.

Minus 1 leaves 9 Minus 6 leaves 4
Minus„ 2 leaves„ 8 Minus„ 7 leaves„ 3
Minus„ 3 leaves„ 7 Minus„ 8 leaves„ 2
Minus„ 4 leaves„ 6 Minus„ 9 leaves„ 1
Minus„ 5 leaves„ 5

What is the difference of 816 and 652?

Fig. 8.

Fig. 8.
Fig. 8.

Put 816 and substract 6 in the hundreds column, by raising the 5-piece and lowering 1 piece below. Then the column will leave 2. Now to deduct 5 in the tens column. But it is impossible to deduct 5 from 1, therefore, take 1 off the hundreds column and fill 5 in the tens column, saying minus five leaves 5. Now, that column reads 6. Lastly, take 2 off 6, by raising the 5-piece and filling in 3 pieces below. 164 is the required answer.

Deduct 997 from 1000.

Minus nine leave 1; clear thousands column and give 1 to the hundreds column. Repeat the process in the tens column. Next, saying minus 7 leave 3, clear the tens column and fill 3 in the unit column, which is the required remainder.

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