20+460+300= 420-50= 620-20= 402+497≈
730+70= 660-130= 290+110= 798-299≈
420 + 390 = 634 - 186=
496+285= 604-439=
593-(271+169)= 358+9×7= (420-380)÷8=
爷爷和王红的年龄之和是71岁,王红和爸爸的年龄之和是43,爷爷和爸爸的年龄之和是100岁。爷爷、爸爸和王红各多少岁?