1
Which is the difference of 55-7?
You may draw place-value blocks.
a. 45
b. 46
c. 47
d. 48
d. 48
Jason wants to find 86-61 using place-value blocks.
Will Jason need to regroup to find the difference? What is correct?
a. Yes; 86 should be regrouped as 8 tens and 16 ones.
b. Yes; 61 should be regrouped as 5 tens and 11 ones.
c. Yes; 86 should be regrouped as 7 tens and 16 ones.
d. No; Regrouping is not needed.
d. No; Regrouping is not needed
Subtract. Use place-value blocks. Show your work.
33-24=___
33-24=9
Subtract. Use place-value blocks. Show your work.
61-3=___
61-3=58
What is the answer called in subtraction?
The difference.
Use any strategy to find 24-16. Show your work. Write the missing part in the bar diagram.
*display bar diagram on white board
24-16= ___
24-16=8
A 5 in the tens place of a number equals 50.
True
Make a plan. Solve each problem. Show your work.
A hardware store has 32 hammers in stock. The store sells 16 hammers on Saturday. How many hammers are left?
___ hammers
16 hammers
Use any strategy to subtract. Show your work.
73-4=____
73-4=69
True or False.
An 8 in the one's place of a number equals 80.
False
Sam has 74 books. He puts 28 books on a shelf. How many books are NOT on the shelf? Show your work.
___ books are NOT on the shelf.
46 books are NOT on the shelf.
Which problem will use regrouping of place value blocks to solve?
a. 54-23
b. 82-44
b. 82-44
Peter collects 54 stamps. He gives 29 stamps to Ruth. How many stamps does Peter have now? Show the problem with a bar diagram with a ? for the unknown number. Then write an equation to solve the problem.
54-29=25
Find 53-27. Use partial differences to solve. Show your work.
53-27=26
53-3=50
50-4=46
46-20=26
Andy's class wants to test samples of river water. They want to test 47 water samples. So far, they tested 34 samples. How many more samples do they need to test? Use a bar diagram to solve.
47-34=13 more samples
A ship has 68 round windows. The ship also has 16 square windows. 7 of the windows are broken. How many windows are NOT broken?
a. 45
b. 61
c. 77
d. 91
c. 77
Claire has 53 beads. Grace has 26 fewer beads. Bella has 39 beads. How many fewer beads does Bella have than Claire?
____ fewer beads
14 fewer beads
Which numbers will complete this partial differences problem for 54-18? Choose all that apply.
*display problem on white board
a. 34
b. 36
c. 44
d. 45
e. 53
b. 36
c. 44
Find 72-38. Use any strategy to solve.
72-38=34
What are three ways to solve a subtraction problem?
Possible answers:
~ place-value blocks
~ 100 chart
~ number line
~ partial differences
Ryan has 46 marbles. John has 4 fewer marbles than Ryan. John gives 9 marbles to his friend.
1. Which pair of equations should be used to find how many marbles John has now?
a. b.
46-4=42 46-4=42
42-9=33 42+9=51
c. d.
46+4=50 46+4=50
50-9=41 50+9=59
2. How many marbles does John have now?
____ marbles.
a.
46-4=42
42-9=33
&
33 marbles.
A book has 72 pages. Dan reads 38 pages on Monday. He reads 26 pages on Tuesday. How many pages does Dan have left to read?
1. Which pair of equations should be used to find how many pages Dan has left to read?
a. c.
38+26=64 72+26=98
72-64= 8 98-38= 60
b. d.
72-38=34 72-26=46
34+26=60 46+38=84
2. How many pages does Dan have left to read?
___ pages.
8 pages.
Fill in the missing digits of this subtraction problem.
_ _ - 23 = 29
52-23-29
Choose all of the problems that you will solve by regrouping if you subtract using place-value blocks. Draw blocks if needed.
a. 45-0=?
b. 68-49=?
c. 84-37=?
d. 99-33=?
e. 78-18=?
b. 68-49=?
c. 84-37=?
What does CUBES stand for?
C- circle the numbers
U- underline the question
B- box the keywords
E- eliminate extra information & evaluate steps
S- solve