Question

Aflati cifrele a b c d e f pt care urmatoarele nr sunt prime (cu bara deasupra) a) 4a , b) 7b c) c3 d)10b e) 21e f) f17

Answer 1

4a-4[4 impartit cu 4]
7b-7 ori 1
c3-3 ori 1
10d-nu convine
21e-nu convine
17f-17 ori 1

Answer 2

a)4a
a€{1,3,7}
b)7b
b€{1,3,9}
c)c3
c€{1,2,4,5,7,8}
d)10d
d€{1,3,6,7,9}
e)21e
e€{1,4,5,7,8}
f)f17
f€{2,3,5,6,8,9}