Question

Câte numere naturale de 6 cifre încep cu 1 ,2,3?

Answer 1

abcdef

a={1,2,3}

b={0,1,2,...,9}

c={0,1,2,...,9}

d={0,1,2,...,9}

e={0,1,2,...,9}

f={0,1,2,...,9}

a x b x c x d x e x f

= {0,1,2,...,9} x {0,1,2,...,9} x {0,1,2,...,9} x {0,1,2,...,9} x {0,1,2,...,9} x {1,2,3}

= 10 x 10 x 10 x 10 x 10  x 3

= 300000 numere