Decimals

We encourage students to connect decimal addition/subtraction to whole number addition/subtraction and line up the place values. Many students will line up the digits and disregard the decimal point/place value.

Example: 12.200

+04.845

To help see the place values they can add 0’s to fill in the empty place values (red above in example)

MULTIPLYING DECIMALS

Blooket Review:

Extra Multiplication Practice work page

Extra multiplication of decimals practice.pdf

mult decimals story probs.pdf

Multiplication of Decimals

Learning Target

I can fluently multiply multi-digit decimals using the standard algorithm for each operation.

Video

Video that goes along with student notes

https://youtu.be/rn5bEyfFAlg

Extra videos

https://www.khanacademy.org/math/arithmetic/arith-decimals/arith-review-multiplying-decimals/v/intro-to-multiplying-decimals
https://www.khanacademy.org/math/algebra-basics/basic-alg-foundations/alg-basics-operations-with-decimals/v/multiplying-decimals
- (At 2:29 the video starts talking about using estimation to confirm your decimal place value; this is something that we stress in class rather than counting decimal places.)
https://learnzillion.com/lesson_plans/4953-multiply-multi-digit-decimals-using-the-standard-algorithm#

Teacher Tips

The primary method for placing the decimal in the answer to a multiplication problem is using estimation. 2.35 x 7.8 could be estimated to find the decimal place in the product. 2.35 is close to 2. 7.8 is closer to 8.

2 x 8 = 16 so in the digits 18330 the decimal would have to go 18.330 because 18 is close to the estimate of 16.

The secondary method, used to check placement. (Note that is may not be accurate if zeros are missing at the end of a number in the answer.)

Interactive Online Practice

https://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-multi-digit-whole-number

grade-6-multiply-two-decimals-0-3-decimal-digits-a.pdf

grade-6-multiply-decimals-by-whole-numbers-0-3-decimal-digits-column-a.pdf

grade-6-multiplying-whole-numbers-and-decimals-hard-a.pdf

DIVIDING DECIMALS

grade-5-division-with-remainder-within-1-100-a.pdf

grade-6-dividing-decimals-by-2-digit-whole-numbers-a.pdf

grade-6-dividing-1-2-digit-decimals-by-whole-numbers-a.pdf

grade-6-decimals-long-division-by-whole-numbers-harder-a.pdf

Repeating vs Terminating Decimals

This is when we have to try to solve to 0 = Terminating

If it doesn't solve to 0 we should see a pattern for a repeating decimal

Division of Whole Numbers

Learning Target

I can fluently divide multi-digit numbers using the standard algorithm. (NS.2)

Videos

Videos that go along with student notes

http://mathantics.com/section/lesson-video/long-division

(This video has a great use of unit vocabulary.) At 9:05 is a common error with students. They fail to place a zero up in the answer to hold the place value.

https://www.khanacademy.org/math/arithmetic-home/multiply-divide/mult-digit-div-2/v/division-2

Interactive Practice Sites

http://kidsnumbers.com/long-division/

Division of Decimals

Learning Target

I can fluently divide multi-digit decimals using the standard algorithm for each operation. (NS.3)

Video

Videos that go along with student notes

Extra videos

Teacher Tips

Division of a decimal by a whole number. Divide like you would whole number standard division. Bring the decimal up into the answer in the same place.

Division of decimal by a decimal: We must create a whole number in the divisor position (outside value). In class we discuss the pattern of multiplying each value, dividend (inside value) and the divisor, by 10 or 100, and how it doesn’t change the answer. That means that you must move the decimal in the dividend the same number of time you move it in the divisor. Then you can divide as you would whole numbers and bumping the decimal up in place in the answer in the same position it is located in the dividend.

Interactive Online Practice

http://www.coolmath.com/prealgebra/02-decimals/10-decimals-dividing-by-decimal-01