23+89+77 = (23+77)+89 = 100+89 = 189
44+78+56 = (44+56) + 78 = 100+78 = 178
223+398+277 = (223+277)+398 = 500+398 = 898
144+578+256 = (144+256) + 578 = 400+578=978
123+289+177 = (123+177)+289 = 300 + 289 = 589
544+278+156 = (544 + 156) + 278 = 700 + 278 = 978