December & January Math Workshop

December and January Math Workshop   

                             

Addition and Subtraction Within 200 with Word Problems to 100

In this 35- day unit, the children will be building fluency in two-digit addition and subtraction within 100 and applying that to one and two step word problems.  They will continue working on place value understanding, which will help them to compose (e.g. bundle ten ones to make 1 ten) and decompose (e.g. breaking apart 1 ten to make 10 ones) place value units to add and subtract within 200. Students will also be adding up to four two-digit numbers using strategies based on place value and properties of operations.  The children will be going from the concrete (e.g. place value materials) to the pictorial (e.g. drawing place value disks) to abstract. For example:

           Concrete                                              Pictorial                             Abstract    

    

Key Vocabulary

• Algorithm: a step-by-step procedure to solve a particular type of problem
• Compose: to make a larger unit from smaller units (e.g. 10 ones = 1 ten or 10 tens = 1 hundred)
• Decompose: to break a larger unit into smaller unites (e.g. 1 ten--> 10 ones or 1 hundred--> 10 tens)
• Simplifying Strategy: e.g. to solve 299 +6, think 299 +1 +5= 300 +5 = 305

How you can help at home:

• Ask how many ones, tens and hundreds are in numbers that you and your child come across when adding and subtracting.
• Encourage your child to make math drawings and use place value language to explain what they are doing when adding or subtracting (e.g. composing or decomposing a ten or hundred)
• Continue to review addition and subtraction skills.