Grade 4 : Length Unit

Dear readers, since I am a math teacher, and I teach grade 4, I wanted to share with you my latest updates concerning this class.So now our new lesson is about length unit which is based on converting units , now at first I began with a story where I told them, that in the old days, the idea of having a property which is yours wasn't yet applied , and neighbors started fighting about the privacy of each land so they created something called length unit which is based on measuring the land in order to know the private area of each family , of course we went a bit far because you also have other units for mass and capacity but it wasn't our subject , then I showed them the table of the length unit and on Monday I will hang the same table in class.

Well to be honest when I started explaining the concept of converting ,they got lost a bit for example they understood the concept of converting from Km to hm that you do ( x 10) , but to convert from Km to dam , they forgot to do 10 x 10 , instead they did 10 + 10 , and I was a bit shocked because it is was written on the board that you should do ( x 10 ), I don't want to seem this bad person who complains about the new generation but honestly , now we are in an era where they never pay attention to small details , they simply want the conclusion which is actually ruining the pleasure of being excited to find out by our self the solution ! Anyways back to the explanation , when we reached converting whole numbers,they were understanding very well , but when we reached the decimal numbers ,here the disasters begun , but the bell rang :/ .
Thus on Monday will sure be a challenge for me to help them get the idea of it ,maybe the best solution is to be slow a bit in this ....Oh and by the way,  I will distribute a small table of the length unit so they can try it by their self, I already did them today so that's a relief .
Please if you have any comments or extra ideas , be free to share them with me :)