Today, isaac needs to walk his dog, water the garden, and feed his fish. d dd is the number of minutes it takes to walk his dog, g gg is the number of minutes it takes to water the garden, and f ff is the number of minutes it takes to feed his fish. the expression g + ( d + f ) g+(d+f)g, plus, left parenthesis, d, plus, f, right parenthesis describes the total number of minutes it takes isaac to do all three tasks. we can also use the expression ( g + d ) + f (g+d)+fleft parenthesis, g, plus, d, right parenthesis, plus, f to represent the same quantity.