Adding in this way is the last of the three modes I was to
describe.
"Now of these three methods the last is undoubtedly the best. If you
once commit the addition table thoroughly, you have it fixed for life;
whereas if you do not, you have to make the calculation over again every
time, and thus lose a vast amount of labor. I have no doubt that there
are some in this class who are in the habit of _counting_, who have
ascertained that seven and eight, for instance, make fifteen, by
counting up from seven to fifteen _hundreds of times_. Now how much
better it would be to spend a little time in fixing the fact in the mind
once for all, and then, when you come to the case, seven and eight
are--say at once 'Fifteen,' instead of mumbling over and over again,
hundreds of times, 'Seven, eight, nine, ten, eleven, twelve, thirteen,
fourteen, fifteen.'
"The reason, then, that some of the class add so slowly, is not,
probably, because they want skill and rapidity of execution, but because
they work to a great disadvantage by working in the wrong way. I have
often been surprised at the dexterity and speed with which some scholars
can count with their fingers when adding, and yet they could not get
through the sum very quick--at least they would have done it in half the
time if the same effort had been made in traveling on a shorter road. We
will therefore study the addition table now, in the class, before we go
any farther.
Pages:
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400