Instructional Sequence for Addition and Subtraction Operations of Decimals
Addition and Subtraction Operations Concepts
Digits of numbers must be added according to their place values.
Digits of numbers must be subtracted according to their place values.
Decimals are another way of writing fractions
Base ten is infinite in both directions
Decimal point can represent "and" when reading decimal numbers.
Decimal point locates the units position.Prior knowledge
Heard of percent
Background information
Number value is the foundation of operations.
Students should be able to estimate to determine a reasonable answer.Sequence of ideas
Whole number place value is connected to decimal number place value
Role of the decimal point
Base ten infinitely large and small
Connect fractions to decimals, decimals are another way of writing fractions - base ten fractions
Explore rational numbers with models
Use friendly numbers (tenths, hundredths, thousandths and percent) for addition and subtraction
Include numbers greater than and less than one
Use friendly numbers (tenths, .25, .5, .50, .75) for multiplication. Invent whole numbers times tenths are tenths, whole numbers times hundredths are hundredths, tenths times tenths are hundredths.
Use friendly numbers for division - There are 12 people and 10 subs. How much subs do each person get? do multiple ways.
Generalize a rule for multiplication and division based on base ten.Activity/Strategy
Review whole number place value
writem read, and say numbers activity
Role of the decimal point
smiley face decimal
Base ten infinitely large and small
strip and square (10x10) model
make a chart of 100Connect fractions to decimals, decimals are another way of writing fractions - base ten fractions
fraction to decimal
decimal to fractionUse friendly numbers (tenths, hundredths, thousandths and percent) for addition and subtraction Include numbers greater than and less than one
strip and square (10x10) model
make a chart of 100
no money or use money to explore decimals
meter stick
circular disksUse friendly numbers (tenths, .25, .5, .50, .75) for multiplication. Invent whole numbers times tenths are tenths, whole numbers times hundredths are hundredths, tenths times tenths are hundredths. Include numbers greater than and less than one
strip and square (10x10) model
make a chart of 100
no money or use money to explore decimals
meter stick
circular disksUse friendly numbers for division - There are 12 people and 10 subs. How much subs do each person get? do multiple ways. Include numbers greater than and less than one
strip and square (10x10) model
make a chart of 100
no money or use money to explore decimals
meter stick
circular disksGeneralize a rule for multiplication and division based on base ten. Include numbers greater than and less than one
strip and square (10x10) model
make a chart of 100
no money or use money to explore decimals
meter stick
circular disksReal world problems with whole, fraction, and decimal numbers to apply all above.
literary connections
Dr. Robert Sweetland's Notes ©