Tenkey Tape: Adding Machine

Tenkey Tape is a 10-key adding machine that keeps every calculation on an editable paper tape. Add up a column of figures, then change any line — every total below it recalculates instantly. THE TAPE • Every entry stays on screen with its operator, its running total and your own comment • Tap any line to correct a figure, switch + to −, or label what it was for • Insert a figure you missed into the middle of a tape; nothing gets retyped • Headings break a long tape into sections you can read back a month later BUILT FOR BOOKKEEPING • Exact decimal arithmetic — no floating-point cent errors • Two tax rates, with +Tax to add tax and −Tax to extract the net from a gross amount • Subtotals that keep going and totals that start a fresh calculation • Memory keys, percentages and a Use Result key to carry a total forward • Decimal places, rounding (5/4, banker's, up, down) and round-each-step…