Well, I've been memorising hiragana lately and I noticed that the writing of さ (sa) and き (ki) is sometimes different...

I saw some writings of さ like this...
Name:  sa.jpg
Views: 13
Size:  9.2 KB

And some like this...

Name:  sa2.jpg
Views: 10
Size:  2.7 KB

And about き, the same thing. Some like this...

Name:  ki.jpg
Views: 10
Size:  9.5 KB

And others like this...

Name:  ki2.jpg
Views: 9
Size:  2.8 KB

I'm just confused whether I should joined the curved line or not. Can anyone please help me ?