FearLess Cheat Engine

hi sorry for the noob question but i want to ask if is it possible to create a negative value in CE
the game i'm play have this item +10% hp, i can edit to make it higher value like +13 +14 +15% etc.... but i want to make it negative like -20% HP, is it possible to do this ? if possbile , how ?

Yes. [Link] or Windows Calculator. Type in decimal value of your choice, take output.

-20 decimal = FFFFFFFFFFFFFFEC hex
-20 (4 bytes) = FFFFFFEC hex

Alternatively in CE enter value in decimal, right click on the item in cheat table and choose -> Show as hexdecimal

you can also create a value like this, IIRC

mov eax,#10 //move int 10 to eax
neg eax //turn value stored in eax to negative