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TOPIC B: Addition and Subtraciton of Decimal Numbers
TOPIC B: Addition and Subtraciton of Decimal Numbers
Dear Family,
Your student is adding and subtracting decimal numbers by using familiar methods. They notice the strategies they used to add and subtract whole numbers and fractions can also be used to add and subtract decimal numbers. Your student estimates to check that their answer is reasonable. They also rename a fraction as a decimal number to solve addition and subtraction word problems.
NEW KEY TERMS
inequality
An inequality is a statement that compares two expressions by using > or <. (Lesson 29)
thousandths
Thousandths are a place value unit. 1 one can be decomposed into 1,000 thousandths. (Lesson 1)
FAMILAR TERMS
associative property of multiplication
bundle
exchange
rename
commutative property of multiplication
compare
distributive property
expanded form
exponent
hundredths
long division
power of 10
round tenths
AT HOME ACTIVITY
Find a sample of our lessons below to help support MATH TALK at home.
Students also have these in their APPLY workbook.
Lesson 9
Add decimal numbers by using different methods.
The methods I can use to add whole numbers, such as number lines, making the next unit, and unit form, are useful for adding decimal numbers. Thinking about adding like units helps me when I add decimal numbers.
EM2_G5_M4_TB_L09_PracticePartner.pdfEM2_G5_M4_TB_L09_PracticeSolutions.pdfLesson 10
Add decimal numbers by using place value understanding.
I can use place value understanding to add decimal numbers by using place value disks or a place value chart. I can record my thinking by using vertical form. Estimating helps me make sure my answer is reasonable.
EM2_G5_M4_TB_L10_PracticePartner.pdfEM2_G5_M4_TB_L10_PracticeSolutions.pdfLesson 11
Subtract decimal numbers by using different methods.
To subtract decimal numbers, I can use different methods, such as unit form, the arrow way, or decomposition, to take from the next unit. A number line can also be a useful model when subtracting decimal numbers by decomposition.
EM2_G5_M4_TB_L11_PracticePartner.pdfEM2_G5_M4_TB_L11_PracticeSolutions.pdfLesson 12
Subtract decimal numbers by using place value understanding.
Similar to subtracting whole numbers, I can use the standard algorithm to subtract decimal numbers when one of the other methods is not efficient. Depending on the numbers being subtracted, some methods are more useful or efficient than others.
EM2_G5_M4_TB_L12_PracticePartner.pdfEM2_G5_M4_TB_L12_PracticeSolutions.pdfLesson 13
Solve word problems involving addition and subtraction of decimal numbers and fractions.
When an addition or subtraction problem gives one number as a fraction and the other number as a decimal number, I can rename one of the numbers so that both are in the same form. Using equivalent fractions allows me to rename the fraction as a decimal number before adding or subtracting.
EM2_G5_M4_TB_L13_PracticePartner.pdfEM2_G5_M4_TB_L13_PracticeSolutions.pdfReport abuse