2. a. a=230,232,234,236,238
b. a=231,234,237
3. a. A={1,2,3,6,9} B={1,2,4,8}
b. AreunitB={1,2,3,4,6,8,9}
AintersectatB={1,2}
B\A={4,8}
4. a. 60=2²×3×5
b. 2160=2⁴×5×3³
5. 42=7×3×2
70= 5×2×7
(42,70)= 2×7=14
[42,70]=2×7×3=42
6. x:2=a rest b
x:3=c rest d
x:5=e rest f
x=2a+b
x=3c+d
x=5e+f => x=[2,3,5]
[2,3,5]=30
x=30
7. 6xy divizibil cu 5
6xy nu e divizibil cu 3
Nr sunt: 605, 610, 620, 625, 635, 640, 650, 655, 665, 670, 680, 685, 695
