Always begin at the top and add downward. Point the place on the paper with the index finger of the left hand. Only take three columns at a time; read the three figures, and then look at the key-board while striking the first two, and read the next three figures while striking the last one of the preceding three. Use the first finger for the hundreds column, the second for the tens column, the third for the units column. Do this every time, so that each finger has one column to attend to, and there is no movement of the hand from left to right and from right to left. When three columns are added, move the hand over on the keys and take the next three columns. Speed in addition comes only from practice on actual work. Twenty minutes a day for sixty days will make a fair speed, and from that on the speed will continue to increase for a year or more.
Some prefer to use four fingers and carry four columns at a time. If one finds the little finger handy it is well to do so. Others prefer to carry all the columns at once, and it is always best to do so when adding scattered items, or direct from checks also when adding cross footings.
We give a few finger exercises on next page, which, if practiced, will help in obtaining control of the muscles of the fingers and familiarize the fingers with the key-board. The key-stroke on the Comptometer is different from that required on a typewriter, therefore typewriter operators will have to learn to give it the proper and natural stroke. On a typewriter the touch must be a quick blow, for the typehead is used as a hammer to strike the impression; but on the Comptometer the touch required is a natural quick downward stroke, not a blow.
