Chapter 3: Adding and subtracting decimals

Lessons

Lesson 1: Decimals on a number line.
Main Idea: Students will represent decimals on a number line. 

Lesson 3: Round large and small numbers. 
Main Idea: Students will round whole numbers and decimals. 

Lesson 5: Estimate very small and very large numbers. 
Main Idea: Students will estimate sums and differences of decimals. 

Lesson 7: Add and subtract decimals
Main Idea: Students will add and subtract decimals.

*According to ehow:  
Clustering Method

• To use the clustering method of estimation, find the best common number that ends in zero that the numbers in your problem cluster around. For example, you might have to add the numbers 29 plus 33 plus 27 plus 28 plus 35. All the numbers seem to cluster around 30. Substitute the cluster number, in this case 30, for each number. You can now use mental math to determine that 30 + 30 + 30 + 30 + 30 gives you an estimation of 150.
  

Vocabulary 

•  clustering
  
•  difference
  
•  equivalent decimals
  
•  front-end estimation
  
•  sum

Resources

Readiness Quiz
Vocabulary Review
Bowl-o-Matic
Adding and Subtracting with Decimals 
Decimals on a Numberline 
Decimal Numberline 
Comparing and Ordering Mount Frost 
End of Chapter Quiz