Why are Symmetric keys shorter than ASyemmetric keys and provide the same level of security.

Hello

Can someone please help me with the following question.

Can someone please give me a brief (if possible) why Symmetric Keys which are much shorter than Asymmetric keys provide a similar level of security (e.g. take as long to crack).

I understand RSA and can to the math with a piece of paper and the Windows advanced calculator (e.g. encrypt and decrypt a sort message using a couple of small prims likes 53 and 59).

I also understand ( to a very basic level) AES e.g. 128bit block cypher (I believe a CBC cypher using an unpredictable IV)

Is there a simple answer if someone says why are Symmetric keys shorted and just as secure or it is just how it is? due to the different math?

Thank you

AAnoterUser__

AAnotherUser__