Three students sorted recyclables from three trash dumpsters. The weight of recyclable

material from each dumpster is listed below. Find the total weight. Notice how the weight is

given in pounds and ounces. To determine the total

weight, we add the ounces and we add the pounds. But if the number of ounces is 16 or more we have to convert the

ounces to pounds and ounces. Let’s first determine the total weight by organizing the weights in a table. Let’s have a column for the ounces and a column for the pounds. We have 12 pounds,

eight ounces, 15 pounds, nine ounces, and at 19 pounds, 14 ounces. Now let’s go ahead and add

the ounces and add the pounds. For the ounces, eight

plus nine plus 14 is 31. We have 31 ounces. And for the pounds, we

have 12 plus 15 plus 19 which is 46, giving us 46 pounds. So the total weight is

46 pounds and 31 ounces. But again, since the

number of ounces is 16 or more, we have to convert the

ounces to pounds and ounces. Let’s write this total weight

as 46 pounds plus 31 ounces. To determine how many

pounds are in 31 ounces we need to determine

how many 16s are in 31. And there’s only one 16 in 31

because 16 times two is 32. So we can write 31 ounces

as 16 ounces plus 15 ounces. And let’s go ahead and do that. 46 pounds plus 31 ounces

is equal to 46 pounds plus 16 ounces, which is

one pound, plus 15 ounces. Again, 16 ounces plus

15 ounces is 31 ounces but 16 ounces is equal to one pound and therefore we can

write this as 46 pounds plus one pound plus 15 ounces. And since 46 plus one

is 47, the total weight in pounds and ounces is

47 pounds, 15 ounces. We can leave this as 15 ounces

because 15 is less than 16. I hope you found this helpful.