Math Strategy: Using the 5 or 10 Anchor

What is "using the five-or-ten anchor"?

Math Strategy: a strategy that involves decomposing numbers to find 5s or 10s for easier calculations

Math strand:  Number Sense and Numeration

English:

French:

Overview: 
In this strategy, students split one or both addends to find anchors of five or ten and the left over amount.  Using the five- or ten-anchor is a foundational skill that helps students see how numbers relate to each other.  When students focus on number relationships and build an understanding of numbers, they are able to see smaller numbers inside of larger numbers.  The numbers 5 and 10 provide the strongest benchmarks for thinking about all other numbers. 

Example:


How this supports student learning:
The recognition of the relationship of all other single-digit numbers to 5, at first, and then to 5 and to 10 helps students to structure their understanding of number around anchors of 5 and 10.  Students benefit from many experiences with making 10 and relating 10 to other numbers before they can develop strategies for the basic facts.  It is important for students to recognize 10 as an anchor number and to be able to identify relationships between it and the numbers 0 to 10.  Using visual models, such as ten frames when introducing basic facts will help students to see that numbers live inside a number.  Knowing how numbers relate to each other will be helpful for students when they learn strategies for composing and decomposing numbers.  Once these facts become automated, it becomes much easier for students to work with larger numbers and apply a variety of other strategies such as Using up/down over 10 and Taking from 10.

Where to next:
To encourage students to build the foundational skills of Making 10, use mini lessons such as Make 10 Sequence (page 200) as well as the following games, Steal the Bundle, Go Fish for 10 and Make 10 Concentration (page 171 – 174) from the text “What to Look For” by Alex Lawson.

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