Basi $111$ iken son iki basamak icin $25$ secenek var. Basi $112$ iken son iki basamak icin yine $25$ secenek var. Yani cevap $11255$ olmali.
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Eger basamaklar farkili ise.
Basta $1$ varken $24$ secenek, $2$ varken $24$ secenek. Yani aradigimiz sayi basta $3$ varken $2$. secenek. Bu da $31254$.