Rekenen met datum en tijd

Aangezien \(t = 1\) overeenkomt met 1 januari, komt \(t = 362\) overeen met \(362 \text{ } \text{januari} \text{.}\)

\(362 \text{ } \text{januari}\)
\(\text{ } = 362 - 31 \text{ (januari)} = 331 \text{ } \text{februari}\)
\(\text{ } = 331 - 28 \text{ (februari)} = 303 \text{ } \text{maart}\)
\(\text{ } = 303 - 31 \text{ (maart)} = 272 \text{ } \text{april}\)
\(\text{ } = 272 - 30 \text{ (april)} = 242 \text{ } \text{mei}\)
\(\text{ } = 242 - 31 \text{ (mei)} = 211 \text{ } \text{juni}\)
\(\text{ } = 211 - 30 \text{ (juni)} = 181 \text{ } \text{juli}\)
\(\text{ } = 181 - 31 \text{ (juli)} = 150 \text{ } \text{augustus}\)
\(\text{ } = 150 - 31 \text{ (augustus)} = 119 \text{ } \text{september}\)
\(\text{ } = 119 - 30 \text{ (september)} = 89 \text{ } \text{oktober}\)
\(\text{ } = 89 - 31 \text{ (oktober)} = 58 \text{ } \text{november}\)
\(\text{ } = 58 - 30 \text{ (november)} = 28 \text{ } \text{december}\)

Aangezien \(t = 0\) overeenkomt met 27 oktober 2022, komt \(t = 106\) overeen met \(27 + 106 = 133 \text{ } \text{oktober} \text{.}\)

\(133 \text{ } \text{oktober}\)
\(\text{ } = 133 - 31 \text{ (oktober)} = 102 \text{ } \text{november}\)
\(\text{ } = 102 - 30 \text{ (november)} = 72 \text{ } \text{december}\)
\(\text{ } = 72 - 31 \text{ (december)} = 41 \text{ } \text{januari}\)
\(\text{ } = 41 - 31 \text{ (januari)} = 10 \text{ } \text{februari}\)
Dus bij \(t = 106\) hoort 10 februari 2023.

21 april 2022 is \(t = 0\)
30 april 2022 is \(t = 30 - 21 = 9\)
31 mei 2022 is \(t = 9 + 31 = 40\)
30 juni 2022 is \(t = 40 + 30 = 70\)
31 juli 2022 is \(t = 70 + 31 = 101\)
18 augustus 2022 is \(t = 101 + 18 = 119\)

\(t = 32\) komt dan overeen met \(\text{2026} + 32 = \text{2058} \text{.}\)

\(\text{2004}\) komt dan overeen met \(t = \text{2004} - \text{1987} = 17 \text{.}\)

De maand januari heeft \(31\) dagen.

De \(5\)e maand van het kalenderjaar is \(\text{mei} \text{.}\)

Op \(t = 1{,}223\) is het \(1 \text{ } \text{uur}\) en \(0{,}223 ⋅ 60 = 13{,}38 \text{ } \text{minuten}\) later dan \(\text{12:00} \text{ } \text{uur} \text{.}\)
Het is dan dus \(\text{13:13} \text{ } \text{uur} \text{.}\)

Om \(\text{9:16} \text{ } \text{uur}\) is het \(4 \text{ } \text{uur}\) en \(16 \text{ } \text{minuten}\) later dan \(\text{5:00} \text{ } \text{uur} \text{.}\)
Dat is dus bij \(t = 4 + {16 \over 60} = 4{,}26666... \text{.}\)

\(17{,}4 \text{ } \text{dagen} = 17{,}4 ⋅ 24 \text{ } \text{uren} = 417{,}6 \text{ } \text{uren}\)

\(192 \text{ } \text{minuten} = 192 : 60 \text{ } \text{uren} = 3{,}2 \text{ } \text{uren}\)

\(0{,}90 \text{ } \text{minuten} = 0{,}90 ⋅ 60 = 54 \text{ } \text{seconden} \text{,}\) dus \(6{,}9 \text{ } \text{minuten} = 6 \text{ } \text{minuten}\) en \(54 \text{ } \text{seconden} \text{.}\)

\(8 \text{ } \text{minuten}\) en \(56 \text{ } \text{seconden} = 8 + {56 \over 60} = 8{,}933... \text{ } \text{minuten} \text{.}\)

\(7 \text{ } \text{dagen} = 7 ⋅ 24 ⋅ 3\,600 = 604\,800 \text{ } \text{seconden}\)
\(13 \text{ } \text{uren} = 13 ⋅ 3\,600 = 46\,800 \text{ } \text{seconden}\)
\(30 \text{ } \text{minuten} = 30 ⋅ 60 = 1\,800 \text{ } \text{seconden}\)
Dus \(604\,800 + 46\,800 + 1\,800 + 12 = 653\,412 \text{ } \text{seconden}\)

\(478\,861 \text{ } \text{seconden} = {478\,861 \over 24 ⋅ 60 ⋅ 60} = 5{,}542... \text{ } \text{dagen}\)
\(0{,}542... \text{ } \text{dagen} = 0{,}542... ⋅ 24 = 13{,}016... \text{ } \text{uren}\)
\(0{,}016... \text{ } \text{uren} = 0{,}016... ⋅ 60 = 1{,}016... \text{ } \text{minuten}\)
\(0{,}016... \text{ } \text{minuten} = 0{,}016... ⋅ 60 = 1 \text{ } \text{seconden}\)
Dus \(5 \text{ } \text{dagen} \text{,}\) \(13 \text{ } \text{uren} \text{,}\) \(1 \text{ } \text{minuten}\) en \(1 \text{ } \text{seconden} \text{.}\)

\(1 \text{ } \text{jaar} = 12 \text{ } \text{maanden}\)