Question Number 162942 by HongKing last updated on 02/Jan/22
$$\mathrm{How}\:\mathrm{many}\:\mathrm{positive}\:\mathrm{integers}\:\mathrm{less}\:\mathrm{than} \\ $$$$\mathrm{500}\:\mathrm{can}\:\mathrm{be}\:\mathrm{formed}\:\mathrm{using}\:\mathrm{the}\:\mathrm{numbers} \\ $$$$\mathrm{1}\:,\:\mathrm{2}\:,\:\mathrm{3}\:\mathrm{and}\:\mathrm{5}\:\mathrm{for}\:\mathrm{the}\:\mathrm{digits}? \\ $$
Answered by som(math1967) last updated on 02/Jan/22
$$\mathrm{3}\:{digitstarting}\:{with}\:\mathrm{1},\mathrm{2},\mathrm{3}\:=\mathrm{4}^{\mathrm{2}} ×\mathrm{3} \\ $$$$\mathrm{2}{digit}=\mathrm{4}^{\mathrm{2}} \:\:\:{unitdigit}=\mathrm{4} \\ $$$${total}=\mathrm{48}+\mathrm{16}+\mathrm{4}=\mathrm{68} \\ $$
Answered by peter frank last updated on 02/Jan/22
$$\mathrm{with}\:\mathrm{repetition}\:\mathrm{or}\:\mathrm{without}\:\mathrm{repetition}? \\ $$
Commented by som(math1967) last updated on 02/Jan/22
$${with}\:{repetition} \\ $$