[billmcneale]

The keyboard on this calculator has the number of keys reduced to the minimum by the use of only three function keys, including a combined "x÷" key.

Here, pressing "x÷" gives the multiplication function if "+=" is subsequently pressed to give the answer, and gives the division function if "-=" is subsequently pressed to give the answer, so:

4 x÷ 2 += gives the answer 8. 4 x÷ 2 -= gives the answer 2.

[2-3-7-43-1807]

nice concept but a very bad choice to illustrate good UI. there is enough space to add a few more buttons with dedicated functions.

[billmcneale]

In 2025, sure. Back when that calculator came out, this kind of saving was probably worth it.

[2-3-7-43-1807]

eh why? believe it or not but they had even keyboards back then with many dozens of keys.