MODULE 4
Lesson 4
Objective
•Add and subtract multiples
of 10 and some ones within
100.
Place Value
• Say the number.
• What digit is in the tens place?
• What’s the value of the 7?
174
• State the value of the 1.
• State the place of the 4.
• Let’s try some more by asking the same questions.
258
734
860 902
Making a Ten Drill
• 7 + ___ = 10
• Let’s find missing parts to make ten. If I say 7, you would
say 3.
• Ready? 7.
• Say the number sentence.
• Let’s try some more numbers:
4
23
3
27
7
42
13
17
48
58
Making the Next Ten to Add
• When I say, 9+4, you say 10+3.
• Ready? 9+4.
• What’s the answer?
• Let’s try some others:
19+4
9+6
8+3
8+5
7+6
7+4
29+4
19+6
18+3
18+5
17+6
17+4
49+4
29+6
48+3
88+5
27+6
67+4
79+4
59+6
Concept Development
• There are 5 yellow cubes. How many
•
•
•
•
linking cubes am I showing in this stick?
How many in this stick?
What is the difference between 8 and 5?
What number sentence could I use to
represent the difference between 8 and
5?
8–5=3.
Concept Development Continued
• Has the difference changed?
• But what new number sentence
can I use to represent the
difference between my two
sticks?
• 9–6=3.
• Is the difference still 3?
• YES!
Concept Development Continued
• I add more to each bar. Did the
•
•
•
•
•
•
difference change?
Let’s test this idea. When we add the
same amount to each number in a
subtraction sentence, the difference
stays the same.
Now let’s try this with a new
problem. 34 – 28
Now that is challenging!
Try this one: 36 – 30.
How did you know the answer so
fast?
Yes! Is it easier to subtract just tens!
Concept Development Continued
• Now, can you tell me how
34 – 28 and my other problem,
36 – 30, are related? Turn and
talk.
• Now how long is each bar?
• We added 2 to each bar to
make the problem easy!
• Now it’s your turn. On your
white board, solve these
problems by making a tape
diagram. Add on to both
numbers to make the problem
easier.
22-8
26-19
33-18
Concept Development Continued
• There are 6 red cubes on one end
•
•
•
•
and 4 red on the other end. How
many yellows are in the middle?
What is the total number of cubes?
Let’s make 2 different addition
sentences. What is the addition
sentence for the total number of
cubes?
Now instead let’s join the 1 yellow
with the 6 red.
How do you know this is true
6+5 = 7+4?
Concept Development Continued
• Let’s use that same idea with
•
•
•
•
•
•
larger numbers to make tens.
Let’s solve 28 + 36.
What does 28 need to be the
next ten?
What is 2 less than 36?
How do you know this is true:
28+36=30+34?
We can also show 2 more for 28
with our number bond.
Let’s write both models in our
journals and explain them to your
partner.
Concept Development Continued
• Let’s do some more practice with the
following problems:
19+35
36+29
78+24
37+46
Story Problem
• Carlos bought 61 t-shirts. He gave 29
of them to his friends. How many tshirts does Carlos have left?
• Solve!
• Share!