Homework for page 20-21 question number 1-4

1.Estimate 6.6 divided by 2.3

6 divided by 2 = 3 > The answer e.) Front- end estimation

Front-end estimation is the highest place value when estimating. 

2. (The picture shown in the booklet) Estimate 6.6 divided by 2 = 3

                      6 divided by 2 = 3 underestimate

                       8 divided by 2 = 4 overestimate 

The answer is a.) Number line estimation

Number line estimation is when you use number line on estimating.

3. [C] 25.73 [ divided by] 3.1 [=] 8.3

24 divided by 3 = 8

27 divided by 3= 9

The estimate suggest an answer between 8 and 9. The answer 8.3 is reasonable.

The answer is b.) Estimate, then use a calculator

4. Divide 20.4 divided by 3.

(The picture shown in the booklet) <3>

                                                              <3>

21 divided by 3 = 7

The answer is around 7. The decimal point goes between the 6 and 8.

The answer for this question is c.) Divided as whole numbers, then estimate to place the decimal

Question for 18 and 22.

18. An package of 500 sheets of paper has a measured height of 51.5 mm.

Question: A) Estimate the thickness of a sheet of paper.

Answer: I estimate that the thickness of a sheet of paper is 0.1 mm.

Question:B) Is the actual thickness of a sheet of paper greater or less than your estimate?

how you know.

Answer: The actual thickness of a sheet of paper is greater the estimated one.Because i rounded 51.5 to 52

22) kyle entered in a snowmobile race.He has to do 5 laps on a 6.37-km course.His time for each lap is 1.35 min, 1.27 min,1.23 min, and 1.22 min.

Question: A) How long does it take him to do 5 laps?

Answer: It take 6.49 mins to finish 5 laps.

Question: B) What is his average speed? Round your answer to the neareast hundreth.

Answer: His average speed is 1.29.

Questions # 8 , 10 , 11

Question 8 : Estimate 28.6 to 28. Next , estimate 5.2 to 5.

28 divided by 5 equals to 5.6 , so 5.6 is the final answer.

Question 10 : Divide $17.99 to 7. The answer is 2.57

Question 11 :

Step 1 : Convert 2L and .355 to mL

2L = 200omL
.355L = 355mL

Step 2 : Think of 2 numbers which are divisible by 355 and the quotient should be 516

1775 divided by 355 equals 5
2130 divided by 355 equals 6

By estimation the answer should be between 5 and 6.

Dividing Decimal Numbers

Question # 4 a) in your textbook : Without using a calculator, place the decimal point in the correct position. Show your thinking.

36.72 ÷ 30 = 1224

Showing my thinking: Use front end estimation. ( taking the first digit)

Step 1: 36.72 will turn into 30.

Step 2: 30 will stay the same. So it will be 30 ÷ 30, 30÷30 = 1

Step 3: Now you know that the answer be approximately 1

Answer: 36.72 ÷ 30 = 1.224

Question # 6 b) in your textbook: Estimate then calculate the answer.

4.56 ÷ 0.8 = ______

Estimation:

Step 1: Round 4.56 to the nearest whole number, which is 5.

Step 2: Change 0.8 to 0.5

Step 3: 5 ÷ 0.5 = 10

Answer: 4.56 ÷ 0.8 = 5.7

Question # 12 in your textbook: A contractor charged $398.75 to move the gravel for a garden. The contractor charges $72.50 per hour. How long did she work? Estimate, then calculate the answer.

Estimation:

Step 1 : Change $ 398.75 to $350.00

Step 2 : Change $ 72.50 into $ 70.00

Step 3 : 350 ÷ 70 = 5. That means the contractor worked for about 5 hours.

Answer: 398.75 ÷ 72.50 = 5.5 , the contractor worked for 5 and half hours.

If you need help on multiplication check this link out.

Dividing Decimals with Money

For your class party, say you'd have to bring cup cakes that are 30 cents each, would 10 dollars be enough for 1 cup cake per student? Estimate then calculate.

Well 10.00 ÷ 0.30 is hard to do, so an easier way is to go 10.00 ÷ 0.50 = 20. Another way it to go 10.00 ÷ 0.25 = 40. The number of cupcakes has to be between 20-40.

Let's say you and 3 friends have to divide orange juice, there's 1.36 liters. How much will each friend get? Estimate then calculate.

1.36 ÷ 4, that's too hard to do so lets just say 1.50 ÷ 4 = 0.375, you can also do 1.30 ÷ 4 = 0.325. Another way is 1.2 ÷ 4 = 0.3 and 1.6 ÷ 4 = 0.4 so the answer has to be around 0.3-0.4.

Here is a video that might make dividing decimals easier

Also here is a link to a fun game for dividing decimals!

Dividing Decimals

pens cost $0.40 you have $6

estimate how many pens can you buy?

answer:12 pens

you change 0.40 to 0.50 and divide 6 by 0.40 and you will get 15.

15 is the total pens if you calculate.

Dividing Decimals

pens cost $0.40 you have $6

estimate how many pens can you buy?

answer:12 pens

you make 0.40 to 0.50 and divide 6 by 0.40 and you will get 15.

15 is the total pens if you calculate.