Ray's New Practical Arithmetic · Arts. 21–25 · Unit 3: Subtraction

11. Subtraction and borrowing

Goal: Your child uses the words minuend, subtrahend and difference, and subtracts with and without borrowing.

⏱ About 35 minutes · 6 steps

You'll need

Short mental problems, the definitions and the minus sign, subtraction when no lower figure is larger, then how to borrow when it is.

Warm-up
Do the book's mental problems aloud:
If you have 9 apples, and give 4 away, how many will you have left?
Frank had 15 cents; after spending 7, how many were left?
The words
Read:
The larger number is called the Minuend; the less, the Subtrahend;
The number left is the difference or remainder. The sign − is called minus, meaning less.
No borrowing
Work the example together:
A man having $135, spent $112: how much had he left?
Write 112 under 135. Units 5 − 2 = 3, tens 3 − 1 = 2, hundreds 1 − 1 = 0. He had $23 left.
Borrowing
Read:
When the lower figure in any order is greater than the upper, a difficulty arises, which we will now explain.
Work the book's example: From 73 subtract 45. We can't take 5 from 3, so we take 1 ten from the 7 tens and make 13 units. 13 − 5 = 8, then 6 − 4 = 2. The difference is 28.
Guided practice
Do the book's problems for Article 24 together, starting with:
A farmer having 245 sheep, sold 123: how many sheep had he left?
Check: 122.
Wrap-up
Mental: 50 − 18? (32.) 100 − 35? (65.) 72 − 9? (63.)

Use bundled sticks or coins: change a dime for ten pennies to show what borrowing really means.

Mark this lesson done