# Addition and Subtraction Facts to 18

**Strand:** Number

**Outcome:** 10

## Curriculum Focus

This sample targets the following changes to the curriculum:

- The specific outcome focuses on applying mental mathematics strategies for the basic addition and subtraction facts to 18; whereas the previous mathematics curriculum specified that Grade 2 students should recall these facts to ten. The previous curriculum specified that students should connect manipulatives, diagrams and symbols, as well as apply a variety of estimation and mental mathematics strategies to addition and subtraction problems. It did not explicitly state what these mental mathematics strategies might be or that these strategies needed to be developed with the basic facts as groundwork for their application to larger numbers. The new curriculum sets out in the specific outcome several of these mental mathematics strategies, so it is clear what is expected: "using doubles; making ten; one more, one less; two more, two less; building on a known double and thinking addition for subtraction" (Alberta Education 2007, p. 65).

**Addition and Subtraction Facts to 18 **addresses the following outcomes from the *Program of Studies:*

## What is a Planning Guide?

**Planning Guides** are a tool for teachers to use in designing instruction and assessment that focuses on developing and deepening students' understanding of mathematical concepts. This tool is based on the process outlined in *Understanding by Design*, by Grant Wiggins and Jay McTighe.

The following steps will help you through the Planning Guide:

See Bibliography for reference information.