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Understanding a few concepts will make this unit go smoothly. If it has been a while since you saw this stuff, don't worry. I will do my best to keep this short.

Coordinate pairs are called that because they come in 2s and always in the same order. They are written in parenthesis, with the first number telling how far to go horizontally, always from the origin. The origin is the starting point, as you would suspect. The origin is found at (0, 0). The second number tells you how far to go vertically from the origin. For example, the coordinate pair (3, 5) means go a distance of 3 horizontally from the origin, and 5 vertically from there. This is the idea behind maps and far more importantly, video games and one board game in particular, Battleship.

Pretty shortly, we will introduce the concept of quadrants. This is because the coordinate pairs can go left of the origin, and below it. Yes, negative numbers appear again, and usefully this time. All this is to get your child ready for algebra of course, and graphing but that is all done on calculators in a few years. Enjoy the simplicity now.

Key vocabulary words

• Origin - the point (0, 0), where everything starts.
• Horizontally or horizon - the idea of across seems to work for many kids, to the right at first and left shortly
• Vertically or vertical - and so does the idea of up here, until the idea of down comes in soon.
• Right angles - the square corner, defined by being 90 degrees. I can't find the symbol on the computer, but you get the point.
• Parallel - lines in a plane that stay the same distance apart and never meet. Think train tracks or siding on a house.
• Rectangle - quadrilateral (4 sided closed figure) with 4 right angles, 2 pairs of parallel lines.