Question

if a=25,b= -40, verify that
(i) a+b is an integer
(ii) ab is an integer
(iii) a+b =b+a, name the property
(iv) /a+b/is always a positive integer
(v) -(a+b)= (-a)+(-b)

Answer 1

(I)a+b=-25+40=15, which is an integer.

(II)ab=-25*40=-100, which is again an integer.

(III)a+b=-25+40=40-25=15=b+a. This is the commutative property.

(IV)|a+b| mean the absolute value of the sum. Which will always be positive. This function is called mod.

(V)-(a+b)=-(-25+40)=-15=25-40=-a-b