Ray's New Intellectual Arithmetic · Lesson L · Unit 6: Money, weights and measures
50. Avoirdupois weight (pounds and ounces)
Goal: Your child knows the table by heart and changes quantities to larger and smaller units.
You'll need
- The book page
- Real measures or coins if you have them
What's in the book
The table: 16 drams make 1 ounce; 16 ounces, 1 pound; 100 pounds, 1 hundredweight; 20 hundredweight, 1 ton. Then problems that change to smaller units (multiply) and to larger units (divide).
The lesson, step by step
Warm up
Ask three or four problems from the last lesson again, out of order. Your child answers and says why.
Show the reasoning
SayHalf a pound is half of 16 ounces, which is 8 ounces.
And backwards: 12 ounces are 12/16, or three-fourths, of a pound.
Work the problems aloud
Read each problem on the page aloud. Your child answers, then explains in a full sentence, the way the book's model solutions do. The problems go like this:
Forty-two ounces are how many pounds?
Reduce 10 lb. 10 oz. 11 dr. to drams.
Ten pounds are what part of a hundredweight?
Ask “Why?”
After each answer ask “Why?” or “How do you know?” Ray's wants the reasoning said aloud, not just the number. If your child stalls, go back to the model and say the first half of the explanation together.
Wrap up
Pick the two problems that were hardest today. Tomorrow, start with those as the warm-up.
Afterwards
Do the rest of the lesson's problems over the next day or two, a few at a time. Move on when your child can explain them without help.
Answers to the book's problems
6) 2 lb 10 oz; 3 lb 5 oz; 4 lb 11 oz; 5 lb 10 oz. 9) 8 oz. 12) 75 dr. 13) 2731 dr. 15) 9075 lb. 16) ¾. 17) ½; ⅝; ⅞. 18) 1/10; 1/5; 1/4; 2/5; 1/2; 3/5; 3/4; 4/5.
Worked out for this site from the scan. If a number in your copy differs, trust the book. Every answer is in Ray's own Key ↗.