Ages and Timelines: Subtraction on the Open Number Line is one of eight units in the Contexts for Learning Mathematics Investigating Number Sense, Addition, and Subtraction (K3) This unit begins with the story of Carlos, an eight-year-old boy who is fascinated by his great-grandfathers thick, beautiful silver hair. His great-grandfather lives in Puerto Rico and Carlos is preparing to meet him for the first time. Having only seen photos of him as a much younger man, Carlos wonders how old his great-grandfather is and how ...
Read More
Ages and Timelines: Subtraction on the Open Number Line is one of eight units in the Contexts for Learning Mathematics Investigating Number Sense, Addition, and Subtraction (K3) This unit begins with the story of Carlos, an eight-year-old boy who is fascinated by his great-grandfathers thick, beautiful silver hair. His great-grandfather lives in Puerto Rico and Carlos is preparing to meet him for the first time. Having only seen photos of him as a much younger man, Carlos wonders how old his great-grandfather is and how many years it will take before he might have hair like that, too. As Carlos begins to investigate these questions, his whole family becomes involved in exploring age differences and figuring out how old they each were when Carlos was born. When Carlos shares his investigation with his teacher, the whole school gets involved in the project. This story context sets the stage for a series of investigations in this unit. Children interview their family members and compare age differences. Timelines are introduced as a context for using the open number linea helpful model used as a tool to explore and represent strategies for addition and subtraction. This unit will focus on the open number line as a model for subtraction. In contrast to a number line with counting numbers written below, an open number line is just an empty line used to record childrens addition and subtraction strategies. Only the numbers that children use are recorded and the addition and subtraction are recorded as leaps or jumps. For example, if a childs strategy for adding 8 + 79 is 79 + 1 + 7, using a landmark number of 80, it would be recorded on the open number line The recording would be similar if a child solves 87 8 by first removing 7 and then 1.Modeling childrens thinking on the open number line helps them move beyond counting one by one for addition and subtraction, to strategies such as taking leaps of ten, decomposing, and/or using landmark numbers. Use of the open number line also encourages discussion of the relationship between addition and subtraction and of the relationship between various problems in which the operation of subtraction can be employedsuch as removal, comparative difference, and finding a missing addend. As the unit progresses, timelines are used to record years of birth, rather than ages. This change in context challenges learners to grapple with larger numbers and with the changing places of the part-whole relations of numbers on the number line. For example, first the number 79 may be marked on the number line as 8 less than 87; then it may be the difference between 2005 and 1926. Several minilessons for subtraction are also included in the unit. These are structured using strings of related problems as a way to guide learners more explicitly toward computational fluency with subtraction. Note: It is expected that children will have had substantial experience with number lines prior to this unit. If this is not the case, you might want to take a look at the unit Measuring for the Art Show, to see how the number line model can be developed. To learn more visit http: //...
Read Less
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
Book is in good condition and may contain underlining or highlighting and minimal wear. The book can also include library labels. May not contain miscellaneous items toys dvds etc. We offer 100% money back guarantee and fast customer support.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
Book has internal/external wear and/or highlighting and underlining. It may have creases on the cover and some folded pages. This is a USED book. Codes have been used. All items ship Monday-Friday within 2-3 business days. Thank you for supporting Goodwill of OC.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
Very Good. Size: 8x0x10; Sticker on front cover of former owner. Some look unused. Priority shipping available on this item. ***No international shipping.