1. MATHEMATICS 4 UNIT 1
LESSON 20
Estimating the Quotient of 3- to 4- Digit Dividends
By 1- to 2- Digit Divisors
Mrs. MAY P. SANTIANO
2.
3. Tell the value of the underlined digit and then round it.
4. Do you love surprises?
When do you give a surprise
to your loved ones?
How do you feel when you
see in their faces that they
like your surprise?
5. Leomar wants to surprise his
mother on her coming birthday
next month. He wants to give
her a bag worth ₱ 475 as a gift.
If he plans to save ₱ 19 a day,
about how many days will he
need to save to be able to buy
the gift?
6. What kind of
son is
Leomar?
Do you also
give
surprises to
your parents?
Why do you
want to
surprise
them?
Do you also
save money?
What are the
given facts?
What is asked in
the problem?
What operations
are you going to
use?
Do we need the
exact/actual
answer in the
problem ? What
word/s suggest
that we need only
to estimate?
7. Estimating is an educated guess. There are times when an estimate is
needed and not the actual one.
Solution to the problem.
So, Leomar needs about 25 days to save to be able to buy the
gift.
8. There are times when compatible numbers
Are used to estimate quotients.
Example.
9. Let us compare the actual answer to the estimated one
How is estimation done in the solution we have in the
problem?
What was done first to the divisor and dividend?
Then, what was cancelled in the rounded divisor and
dividend?
Then, what was done next?
• Are the quotients the same or different?
• How near or far is the estimated answer to the
actual one?
• What will you do if the estimated answer is too
large or small compared to the actual one?
10. There are times that the
estimated answer is too large or
small if we round both the
divisor and the dividend to the
highest place value. One way to
make our estimated answer
reasonable or close to the exact
answer is by using compatible
numbers.
11. Study the solutions below
Rounding Method Compatible Number Method Actual Answer
12. Answer: He needs 70 baskets with 24 pieces each and
one basket with 14 mangoes. If the compatible
method is used, he needs about 80 baskets. If the
rounding method is used, he needs about 100
baskets.
Which of the two estimates is closer to the
actual answer?
About 80 baskets is the closer estimate to the
actual answer
13. A.In your notebook, estimate the
following using the Rounding Method:
1] 573÷6=
2] 8501÷9=
3] 8645÷32=
4] 2926÷47=
5] 4108÷82=
14. B. Estimate the following using
the Compatible Number Method:
1] 36 200÷56=
2] 3 209÷18=
3] 4 567÷93=
4] 7 331÷34=
5] 9 536÷16=
16. To estimate quotients, round
the divisor to the highest place
value and use compatible numbers
for the dividend to divide. This
will make your estimated
quotients reasonable.
17. 1. About how many 23s are there in 4323?
2. About how many 52s are there in 1322?
3. About how many dozens are there in 105 pieces?
4. About how many minutes are there in 3578 seconds?
5. About how many 26s are there in 5889?
A. Estimate the answers to the following.
18. 1. 1920 ÷ 6 < 300 or > 300?
2. 2040 ÷ 5 < 300 or > 300?
3. 3473 ÷ 5 < 400 or > 400?
4. 367 ÷ 7 < 50 or > 50?
5. 6575 ÷ 8 < 800 or > 800?
B. Use estimation to tell whether the exact
quotient is less than or greater than the given
number.
19. 1. Which is a better buy. 1 box of 6 pencils at ₱ 27 or 1 pencil at ₱
5 each? Why?
2. If a kilogram of siniguelas costs ₱ 60, about how many
kilograms can you buy with your ₱ 200?
3. Which would you buy, 1 kilogram of powdered detergent at ₱
280 or 6 small packs of 54 grams of the same detergent at ₱ 94?
Why?
B. Answer the following problems
