U mean true numbers? which contain both negative and positive numbers including zero...so...remembering... when summing some negative numbers [(-2)+(-3)+(-5)+(-8)]=[-(2+3+5+8)]=-18...so excluding the negative sign then sum the numbers as positive ones then we put the negative sign to final result..
when summing negative and positive numbers we substrate (lower number from higher one)and the final result will take the sign[whether (+) or (-)] of the higher number (-15)+(10)=[-(15-10)]=-5...(-20)+(35)=[+(35-20)]=+15=15..(-5)+(-9)+(6)+(7)=[(-14)+(13)]=[-(14-13)]=(-1) in multiply take this (Negative*Negative)=positive....(-5)*(-6)=+30=30... (Negative*positive)=Negative ..(-2)*(4)=(-8) the same way in dividing operation...negative/negative=positive....positive/negative=negative.. negative/positive=negative..(-8)/(2)=(-4)..(-25)/(-5)=5.. i hope that would explain something to u