(115+85)9 = 2009 = 1800(500+45):5 = 545:5 = 109(640+60)7 = 7007 = 4900(184+116):3 = 300:3 = 100(670+30)6 = 7006 = 4200(720+80):8 = 800:8 = 100
(115+85)9 = 2009 = 1800
(500+45):5 = 545:5 = 109
(640+60)7 = 7007 = 4900
(184+116):3 = 300:3 = 100
(670+30)6 = 7006 = 4200
(720+80):8 = 800:8 = 100