We are working on modeling multiplication of decimals and whole numbers. They have examples from the classroom to help them with this, but you can use the image above to know what the different place values look like using base ten blocks.
Tuesday, September 28, 2010
Modeling Decimals
We are working on modeling multiplication of decimals and whole numbers. They have examples from the classroom to help them with this, but you can use the image above to know what the different place values look like using base ten blocks.
Wednesday, September 22, 2010
Multiplying Decimals Patterns Practice
1 x 1,000 =
1 x 100 =
1 x 10 =
1 x 1 =
1 x .1 =
1 x .01 =
1 x .001 =
.5 x 1,000 =
.5 x 100 =
.5 x 10 =
.5 x 1 =
.5 x .1 =
.5 x .01 =
.5 x .001 =
45 x 1,000 =
45 x 100 =
45 x 10 =
45 x 1 =
45 x .1 =
45 x .01 =
45 x .001 =
I will add answers tomorrow.
1 x 100 =
1 x 10 =
1 x 1 =
1 x .1 =
1 x .01 =
1 x .001 =
.5 x 1,000 =
.5 x 100 =
.5 x 10 =
.5 x 1 =
.5 x .1 =
.5 x .01 =
.5 x .001 =
45 x 1,000 =
45 x 100 =
45 x 10 =
45 x 1 =
45 x .1 =
45 x .01 =
45 x .001 =
I will add answers tomorrow.
Multiplying Decimals
We have just begun to talk about what happens to a number when it is multiplied by 10, 100, 1,000, .1, .01, and .001.
For example, when 9 is multiplied by the numbers, you would see:
9 x 10 = 90
9 x 100 = 900
9 x 1,000= 9,000
9 x .1 = .9
9 x .01 = .09
9 x .001 = .009
This shows us that a number multiplied by a 10 will get larger by one place value (9 was a ones but when multiplied by 10, it becomes 90 (or a tens)) and each multiple of ten causes the whole number to grow by that many place values (9 x 100 will grow two place values, 9 x 1,000 will grow by 3 place values, etc...)
On the other hand, if a number is multiplied by a decimal number, then the number will decrease by that number of place values (9 multiplied by .1 will go from a 9 (which is in the ones) to a .9 (which is in the tenths place value) and each time the decimal increases, the number will get smaller than number of place values (9 x .01 will go back two place values, 9 x .001 will go back 3 place values).
More Examples:
3.25 x 1,000 = 3,250
3.25 x 100 = 325
3.25 x 10 = 32.5
3.25 x 1 = 3.25
3.25 x .1 = .325
3.25 x .01 = .0325
3.25 x .001 = .003
.4 x 1,000 = 400
.4 x 100 = 40
.4 x 10 = 4
.4 x 1 = .4
.4 x .1 = .04
.4 x .01 = .004
.4 x .001 = .0004
When multiplied by a whole number, the decimal moves to the right making the number larger; however, when multiplied by a decimal number, the decimal moves to the left making the number smaller in value.
For example, when 9 is multiplied by the numbers, you would see:
9 x 10 = 90
9 x 100 = 900
9 x 1,000= 9,000
9 x .1 = .9
9 x .01 = .09
9 x .001 = .009
This shows us that a number multiplied by a 10 will get larger by one place value (9 was a ones but when multiplied by 10, it becomes 90 (or a tens)) and each multiple of ten causes the whole number to grow by that many place values (9 x 100 will grow two place values, 9 x 1,000 will grow by 3 place values, etc...)
On the other hand, if a number is multiplied by a decimal number, then the number will decrease by that number of place values (9 multiplied by .1 will go from a 9 (which is in the ones) to a .9 (which is in the tenths place value) and each time the decimal increases, the number will get smaller than number of place values (9 x .01 will go back two place values, 9 x .001 will go back 3 place values).
More Examples:
3.25 x 1,000 = 3,250
3.25 x 100 = 325
3.25 x 10 = 32.5
3.25 x 1 = 3.25
3.25 x .1 = .325
3.25 x .01 = .0325
3.25 x .001 = .003
.4 x 1,000 = 400
.4 x 100 = 40
.4 x 10 = 4
.4 x 1 = .4
.4 x .1 = .04
.4 x .01 = .004
.4 x .001 = .0004
When multiplied by a whole number, the decimal moves to the right making the number larger; however, when multiplied by a decimal number, the decimal moves to the left making the number smaller in value.
Monday, September 20, 2010
Comparing Decimals Practice
Directions:
For each problem use the greater than ( >), less than (<), or equal symbol to compare the decimals.
1. 3946.55212 _______ 3964.55212
2. 0.84 _______ 0.48
3. 0.98 _______ 0.031
4. 0.99 _______ 0.12
5. 7069.92716 _______ 7096.92716
6. 0.59 _______ 0.51
7. 0.39 _______ 0.065
8. 0.7650 _______ 0.765
9. 0.78500 _______ 78.5
10 0.029516 _______ 0.029539
11 0.04625600 _______ 0.046264
12. 0.9450 _______ 9.45
13. 0.3890 _______ 0.389
14. 0.998 _______ 0.096
15. 925.590085 _______ 925.590022
16. 0.84 _______ 0.095
17. 0.97 _______ 0.79
18. 5521.912210 _______ 5512.91221
19. 0.1350 _______ 0.135
20. 0.925 _______ 0.01
Comparing Decimals
Your child has a study guide to use to help them study for comparing decimals; however, if they have left it at school, then use the below steps to compare decimals.
Step 1: Line up decimals (If it is a whole number without a decimal, then put the decimal at the end of the number behind the ones place).
Example: 15 and .15
15.00
00.15
Step 2: Look at your numbers from left to right because the left side is the greater value and the values decrease as you go toward the right.
Example: For 15 and .15 we start with the tens place and move toward the hundredths place. The 1 and 0 at the front are in the tens place and the 0 and 5 at the end are in the hundredths place.
Step 3: Find the first place where the numbers differ and circle those 2 digits.
Example: I would circle the 1 and 0 in the tens place because they are different and they are the first numbers are different from the left to the right.
Answer: 15 > .15
< means less than, > means greater than, and = means equal to
Go to my website for practice: sites.google.com/site/mrshallumsonlineclassroom
Have a great night!
S. Hallum
Step 1: Line up decimals (If it is a whole number without a decimal, then put the decimal at the end of the number behind the ones place).
Example: 15 and .15
15.00
00.15
Step 2: Look at your numbers from left to right because the left side is the greater value and the values decrease as you go toward the right.
Example: For 15 and .15 we start with the tens place and move toward the hundredths place. The 1 and 0 at the front are in the tens place and the 0 and 5 at the end are in the hundredths place.
Step 3: Find the first place where the numbers differ and circle those 2 digits.
Example: I would circle the 1 and 0 in the tens place because they are different and they are the first numbers are different from the left to the right.
Answer: 15 > .15
< means less than, > means greater than, and = means equal to
Go to my website for practice: sites.google.com/site/mrshallumsonlineclassroom
Have a great night!
S. Hallum
Wednesday, September 8, 2010
New Unit
We are beginning a new unit in math about decimals. Right now we are working with place value from millions to thousandths. Your child has a study guide that they can use to help practice this skill. Above you can find practice problems you can work with to make sure your child understands the different place values.
Have a wonderful week!
S. Hallum
Thursday, September 2, 2010
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