Ray's New Intellectual Arithmetic · Lesson VI · Unit 1: Adding and subtracting in your head

6. Subtraction

Goal: Your child subtracts small numbers in stories and drills, and knows the words minuend, subtrahend and difference.

⏱ About 20 minutes · 5 steps

Open it at the Internet Archive ↗

You'll need

  • The book page (press “📖 Book page”, or use a printed copy)
  • Paper for jotting, though the work is meant to be done in the head

What's in the book

Twenty-five word problems and drills such as “Two from 6 leaves how many? From 7?”, answered as “Ans. 1. Why? Because 1 from 2 leaves 1.” Then the definitions: subtraction, minuend, subtrahend, difference, and the sign − (minus).

The lesson, step by step

  1. Warm up

    Ask three or four problems from the last lesson again, out of order. Your child answers and says why.

  2. Show the reasoning

    SayJoseph had 3 apples and lost 1. He had 2 left. Why? Because 1 from 3 leaves 2.

    Point out that subtraction finds the difference between two numbers. The bigger one is the minuend, the one taken away the subtrahend.

  3. 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:

    Joseph had 3 apples and lost 1: how many had he left?

    Three from 6 leaves how many? From 7? 8?

    A load of corn sold for 17 dollars; the seller took a barrel of flour worth 6 dollars and the rest in money: how much money?

  4. 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.

  5. 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

1) 1. 2) 2. 3) 3. 5) 2. 6) 3. 8) 2. 10) 5. 12) 5. 14) 5. 16) 5. 18) 5. 20) 4. 22) 12. 23) 4 years. 24) $11. 25) 8.

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 ↗.

@teddyrookbook GitHub