Developmentally, educational experts agree that children are ready to learn negative numbers at the age of 11 or 12. The at-grade level learner should have the foundation of mathematical knowledge necessary to comprehend integers by sixth grade. Advanced learners might be ready to embrace this concept slightly earlier, while the struggling learner may need to be provided with more opportunities for instruction and practice before mastering this topic.
Building Number Sense
Number sense is an understanding and awareness of what numbers are and their relationship to one another. A good analogy is that number sense is similar to a skyscraper that must have a firm foundation, then layers are added on gradually. A child must have a firm grasp of numbers greater than one and how those numbers increase and decrease as they are added, subtracted, multiplied and divided before they can be expected to comprehend the abstract concept of negative numbers.
Common Core State Standards
As of the date of publication, 45 states have adopted the Common Core State Standards, an initiative developed during the past several years with the goal of making our public educational system more uniform from state to state 12. According to the National Governors' Association, the governing body of the CCSS initiative, public schools in the United States will introduce the concept of negative numbers in grade 6 as part of the students' study of the number system 2.
Introduction to Negative Numbers
Common Core State Standard 6.NS.C.5 states that "positive and negative numbers are used together to describe quantities having opposite directions or values." Some common examples include rising and falling temperatures, credits and debits in banking, and elevation above and below sea level. Students will use these real world examples to help create an understanding that they can apply to more complex mathematical situations in later years. To build understanding, students will likely use number lines and drawings to help them visually interpret numbers less than zero.
Further Information
Some states, including Massachusetts, have added slightly more stringent standards and have set the expectation that negative numbers be introduced in grade 5. As years go on and each state's transition to the Common Core is complete, it is possible that this skill might move to grade 5 for all states. However, because of the need for a strong foundation of number sense, it is unlikely that negative numbers will be taught at an age much younger than 10.