Tangents – trigonometry – math
Tangents: This line is tangent to a circle. What is a tangent? A tangent, like a sine or a cosine, is a mathematical way of thinking about a kind of movement that happens [...]
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07, 2017
Sine waves – trigonometry – math
Sine wave In order to save energy, many, many things in nature move in a kind of repeated pattern we call a sine wave: water waves, sound waves, light waves, [...]
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07, 2017
Trigonometry and triangles
An infinite distance: stars in the sky Since the time of the Sumerians, about 3000 BC, scientists have studied the stars and the planets. They've tried to figure out the patterns in the movements of [...]
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07, 2017
Cosine – Trigonometry – Math
Right triangle and cosine What is a cosine? A cosine, like a sine, is a mathematical way of thinking about a kind of movement that happens in nature. A cosine is [...]
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07, 2017
What is zero? Zero and place value
A math problem showing place value How can you add big numbers without an abacus? You still group the sheep (or whatever) just as you did when you were using the abacus, but [...]
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07, 2017
Subtraction – reverse addition!
A boy walking backwards Subtracting numbers is just the same as adding them, only walking the other way along the number line. To subtract 3 from 8, you start on the number [...]
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07, 2017
Multiplication and multiplication games
Walk along a chalk line Multiplying numbers is like jumping along the number line, with all your jumps the same size. It's the same thing as addition, except that you repeat [...]
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07, 2017
Simple operations – fun with math
Walk along a chalk line The four basic things you do with numbers are addition, subtraction, multiplication, and division. Each of these is basically a way of describing how fast you are moving along [...]
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07, 2017
Commutative project – Chalk number line
Walk along a chalk line To get to understand the number line better, mark out a line on the playground or on the sidewalk outside your house with chalk. At the middle of [...]
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07, 2017
Division – math operation
How many of these things can I fit into these boxes? Division is a way of answering the question: how many of these things can I fit into that box? [...]
