answer
1385
explanation
to find the total, subtract the amount they earned by the amount they spend
total = earned - spent
earned
each week, Mr. Smith earns 1900 and and his earns 1150, so add these values together to find the total amount they earn
earned = 1900 + 1150
earned = 3050
spent
they spend money on food, gas, mortgage, and savings, so add these values together to find the total amount they spend
spent = food + gas + mortgage + savings
spent = 300 + 90 + 875 + 400
spent = 1665
total
now that we know how much they earn and spend, we can find the total
total = earned - spent
total = 3050 - 1665
total = 1385
every week they have 1385 left over
