1. Traveling from Nasty Problems to Nice Ones
SUBTRACTION REVIEW
Using Compliments
Traveling from Nasty Problems to Nice Ones
Math Grade 6
by Beckey Townsend

2. VIDEO LESSONS
Remember “subtract the ones” strategy from previous grades
((3:12)
Remember “Left to Right” subtraction
(3:37 min)
Remember “Model Drawing” for a subtraction word problem
(5:44 min)
Remember Standard Algorithm
(6:56 min)
Shows base ten block pictures
(9:08 min)
Mental Math Trick “Counting Down” + “Round Up”
(6:57 min)
(8:17 min)
(8:17 min)

3. Try it using the other compliment: Convert 73 to 80
Using Compliments to
Change Nasty Subtraction Problems into Nice Ones
COMPARE TO:
Standard Algorithm
6 13 73
-46 27 73
-46
+4 = 77
+4 = 50 77
-50 27
Try it using the other compliment:
Convert 73 to 80

4. PRACTICE: Change these nasty subtraction numbers into nice ones by using compliments58 94 45 63
-19
-27
-36
-45
Explain HOW to use this compliment method for subtraction and WHY it works.
WHY?

5. EXIT TICKET
TODAY WE LEARNED …
… to use compliments to “make tens” before subtracting.
… tell HOW to use compliment method and explain WHY it works.
… to practice fluency for subtraction.
Grab your student assignment sheet, and your math journal slip.
Complete the “exit ticket” assignment and turn it in to the teacher.
Continue working on the rest of the assignment sheet. If it is not finished in class, then it must be completed for homework.