Time recommended: 10 minutes
Begin with the usual Calendar Time activities and a few additional ones.
Time recommended: 45 minutes
Vocabulary (spoken only)
| difference | follow |
| calculate | reversal |
| reverse | relationship |
| connection |
Today, your student will focus on related subtraction facts.
The task of learning basic subtraction facts is greatly simplified once the student realizes the following concepts:
There is a relationship between facts.
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A larger number cannot be subtracted from a smaller number; for example, 7 - 3 is not the same as 3 - 7.
Note that the student will be subtracting larger numbers from smaller ones at a more advanced stage of mathematical learning, but it is not necessary to make this distinction at your student's stage of development.
Read the following verse aloud twice. This verse is adapted from the traditional verse "A-Hunting We Will Go."
Subtracting We Will Do
Subtracting we will do.
We'll subtract 2 teddy bears
from 5 teddy bears,
And then we'll figure out the difference.
And then we'll figure out the difference.
Repeat the verse, but this time reverse the number that is subtracted and the number that shows the difference.
Subtracting we will do.
We'll subtract 3 teddy bears
from 5 teddy bears,
And then we'll figure out the difference.
And then we'll figure out the difference.
If the student does not point out that the number to be subtracted and the number that shows the difference can be reversed, focus attention on this fact.
Point out, as well, that a larger number cannot be subtracted from a smaller number.
Repeat the verse a few more times, reversing the number that is subtracted with the number that shows the difference. Have the student print a matching number sentence each time.
Continue until the student sees a connection between related subtraction facts or until the child shows signs of fatigue. Return to the activity later, if necessary.
1. Related Subtraction Pages
Ask your student to show how a number that is subtracted and a number that shows the difference can be reversed. Have the student work with differences no greater than ten.
2. Calculator Time
For about five minutes, have your student use a calculator to subtract one number from another number that is no greater than ten. Then make the difference become the number that is subtracted, and have the student observe what happens.
1. The Flip Side
For this activity, you will need the zero to ten number cards,
20 counters (ten of one colour and ten of another colour), and the subtraction-sign and equals-sign cards.
Step 1: Shuffle the number cards, and place them face down on the table.
If the second number picked is larger than the first number, return it to the bottom of the pile. Continue picking cards until a smaller number is chosen. Then place a corresponding set of different-coloured counters above that card.
Place the equals sign beside the second number card.
Step 4: Ask the student to subtract the second number from the first number and print the answer on a blank index card.
Step 5: Have your student show the flip side of the number sentence by moving the cards and counters to reverse the order of the number that is subtracted and the number that is the difference.
Question your student about this reversal of numbers to be sure the student understands the relationship.
Step 6: Repeat Steps 2 to 5 with other number cards.
2. The Other Way
Step 1: Print a column of subtraction facts to ten on the left side of a sheet of loose-leaf paper. Draw a vertical line down the middle of the page.
Step 2: On the other side of the line, print the related subtraction facts with one number omitted from each.
Step 3: Have the student print in the missing number for each related subtraction fact.
Step 4: Take turns listing different subtraction facts and related facts and providing the missing numbers.
Next, follow the directions to do Day 7: Assignment 2.
Then complete Day 7: Learning Log. Under Student's Thoughts, help the student complete the sentence starters.
