Using a classic calculator (i.e. one that doesn't obey operator precedence and thus doesn't need parentheses) that's three operators (including "equals") and a total of 10 buttons to press.
56 - 22%
That's 6 buttons to press. Arguably, 6 is less than 10 [citation needed]. But I find it doubtful that this saves a noticeable amount of effort.
If you're multiplying by decimals, you already read "22%" as "0.22" and "-22%" as "(1 - 0.22)". There's no mental overhead in typing that unless you mean rote copying.
Maybe this is a matter of school system priorities. In my country children are introduced to percentages using cross-multiplication. They are also required to write the entire calculation process down in exams in order to pass (to make sure you actually understand the calculation and aren't just blindly entering numbers into a calculator).
Using a classic calculator (i.e. one that doesn't obey operator precedence and thus doesn't need parentheses) that's three operators (including "equals") and a total of 10 buttons to press.
56 - 22%
That's 6 buttons to press. Arguably, 6 is less than 10 [citation needed]. But I find it doubtful that this saves a noticeable amount of effort.
If you're multiplying by decimals, you already read "22%" as "0.22" and "-22%" as "(1 - 0.22)". There's no mental overhead in typing that unless you mean rote copying.
Maybe this is a matter of school system priorities. In my country children are introduced to percentages using cross-multiplication. They are also required to write the entire calculation process down in exams in order to pass (to make sure you actually understand the calculation and aren't just blindly entering numbers into a calculator).