The US post office sets a size and weight limit on boxes or packages.

The weight limit is 70 lbs.
The size limit is: the circumference plus the length cannot exceed 108 inches.

Angie didn't know this. She stood in line for 35 minutes at the Anchorage airport post office with seven boxes. Three of them were unacceptable. One was overweight. Two were too large. She was frustrated, as she had a plane to catch the next morning and still had errands do.

She vowed that she wouldn't stand in line again that long with boxes she had to return to the truck.

Formula substitution
Greater than/less than
Weight subtraction
Deductive thinking

Parcel Post Limits


Circumference is the distance around the box or package. The length is the longest measurement.

She then understood the post office formula.
C + L cannot be greater than 108" or
C+L > 108"

She measured one of her rejected boxes.

How many inches was it over the limit? She measured the second one. How many inches was that over the limit? Remember, the length is the longest measurement.

Parcel Post Limits

She couldn't get the heavy box on the bathroom scale without covering the dial. She let her son hold the box in his arms, weighing himself and the box together. Angie read the scale. The total was 175 lbs. He weighs 100 lbs. She subtracted his weight from the total to get the weight of the box. How much did the box really weigh?

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How many pounds did she have to remove to get it down to 70 lbs? She took out a few more objects to allow for possible error in the bathroom scale. She didn't want to wait in line twice for the same box ever again!

The next trip to town she had five boxes with the following measurements. Which ones were over the size limit? Before she filled and taped them, she cut the oversize ones to size.

Francine then weighed them. What was the actual weight of each box if her son held them in his arms on the bathroom scale? He still weighs 100 lbs.

Parcel Post Limits
She took some weight out of the overweight ones and taped each one thoroughly.

She stood in the post office line with total confidence this time.

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