Math Lesson for Virtual Tutoring

1. Subtracting 3, 4, 5 digit
numbers
Week 4 :
Natalie and Karen

2. This is going to work a lot like subtracting with two
digit numbers...
639-275
Our first step is to stack and line things
up:

3. As usual, the first thing to do is to subtract the
ones... We don't have to do any borrowing on this
one:
639
-275

4. Now, we'll subtract the tens
stripe... But, we run into that
problem again!
639
-275
We can’t subtract 7 from 3, since 7 is
bigger than 3.

5. Subtract the tens... Then, subtract
the hundreds...
539
-275
364
OK, now we're ready to do one with TWO borrows in
it! And I'm going to use the faster way to show my
work so you can get used to it.

6. Now let’s work through a few sample
problems together
584
-377
924
-368

7. Lets work on word problems.
A word problem can have lots of information. You need to identify
what information is available and determine what is it asking.
Let’s look at the first example:
Molly works at a women’s clothing store. Yesterday, she noticed
that all her customers wore pants or skirts. 2 customers wore
pants and 3 customers wore skirts. How many customers did Molly
help yesterday. Circle your answer
3 4 5 2

8. Sara wrote 524 words in her journal. Then she crossed out
56 words and added 95 new words.
a. How long was the entry after she crossed out words?
_______
b. How long was the entry after she added new words?
_______