1)
what's 4/7 of 14? well, is just their product
[tex]\bf \cfrac{4}{7}\cdot 14\implies \cfrac{4}{7}\cdot \cfrac{14}{1}\implies \cfrac{4}{1}\cdot \cfrac{2}{1}\implies \cfrac{4}{1}\implies 4[/tex]
2)
let's say the number is "x", then,
[tex]\bf \cfrac{2}{3}x=10\implies \cfrac{2x}{3}=10\implies 2x=30\implies x=\cfrac{30}{2}\implies x=15[/tex]