Question 186
a) A country calculator of Cincoland has only the digits from 0 to 9 and two buttons $\square$ and $\triangle$. The $\square$ button squares the number on the calculator display. The $\triangle$ button subtracts 5 from the number on the calculator display. Monica enters the number 7 and then presses $\square$, then presses the $\triangle$ button. What is the result shown by the calculator?
b) Shows that if a natural number $x$ leaves a remainder of 4 when divided by 5, then the number $x^{2}$ leaves 1 when divided by 5.
c) Cincoland's calculator, is it possible to type the number 9 and then reach the result 7 by pressing the buttons $\square$ or $\triangle$ properly?
b) Shows that if a natural number $x$ leaves a remainder of 4 when divided by 5, then the number $x^{2}$ leaves 1 when divided by 5.
c) Cincoland's calculator, is it possible to type the number 9 and then reach the result 7 by pressing the buttons $\square$ or $\triangle$ properly?