This IAE Blog entry is based on “The Calculating Brain,” written by Stanislas Dehaene (2010). It is chapter 9 in *Brain, Mind, and Education* (Sousa, 2010). Dehaene has long been a world leader in research on the brain science of children developing arithmetic knowledge and skills.The following are some of the ideas discussed in Dehaene's chapter.

- An undamaged infant’s brain has innate ability to distinguish between 1, 2, and 3 objects. This level of exactness serves as a starting point for eventually learning the math language and notation for dealing with larger quantities and with a number line of evenly spaced numbers.
- The infant’s brain also has innate ability to deal with approximations. Humans and some other animals can tell when one group of objects is larger than another. For example, a small pride of lions that encounters a much larger pride of lions will retreat to avoid a confrontation. A human toddler can distinguish a difference when the ratio of objects in two sets is two to one (such as eight objects versus four objects). This ability improves as a brain matures, so that a typical adult is able to distinguish a difference when one set of objects is about 1.15 times as large as another set.

Math education builds on these two innate abilities. It takes a lot of education to bring these innate skills to the contemporary standards we expect in arithmetic.