The addition rule in modular arithmetic shows that when \(a,b,c,\) and \(d\) are integers and \(m\) is also a positive integer then,\(a+b\equiv c+d\) (mod \(m\)) , where \(a\equiv c\) (mod \(m\)) and \(b\equiv d\) (mod \(m\)). The subtraction rule is similar, \(a-c\equiv b-d\) (mod \(m\)).