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Sterling Middle School Math
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Parabolas - Moving around
What is the equation of a parabola of the standard shape, facing upward, that has a vertex of (3,2)? y=(x-3)^2+2 a vertex of (-4,-5)? ...
Tom Keeler
Mar 251 min read
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Sides of squares
What is the length of the side of a square whose area is 5? The square root of 5.
Tom Keeler
Mar 251 min read
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Triangles and degrees
How many degrees are in the three angles of a triangle? 180 How many degrees are in each of the angles of an equilateral triangle? 60 ...
Tom Keeler
Mar 251 min read
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When does a new number family start?
When counting by powers of ten, a new family starts every multiple of 3. 10^3 is the start of the thousands family, 10^6 is the start of...
Tom Keeler
Feb 261 min read
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Move a parabola to the right
You move a parabola to the right by subtracting from x. For example, y=(x-4)^2 moves the vertex of the parabola from the origin (0,0) to...
Tom Keeler
Feb 261 min read
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One away from a perfect square
How much less is the product of two numbers that are one more and one less than a perfect square? For example, how much less is...
Tom Keeler
Feb 121 min read
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One square to the next n+n+1
After practicing the squares of the multiples of 10, 10x10, 20x20, etc., next look at the squares that are one bigger: 11x11, 21x21, etc....
Tom Keeler
Feb 111 min read
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Why not 10,000?
Ask your student how many perfect squares are less than 10,000. (note: 100*100 = 10,000, so 1 squared up to 99 squared must be less than...
Tom Keeler
Feb 101 min read
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table to function - linear vs exponential
How do you know from a table if the function is linear or exponential? In the example below, for each step of x, the y is multiplied by 2....
Tom Keeler
Feb 51 min read
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solid vs hollow dot
When drawing an inequality, what is the difference between the hollow and a solid dot?
Tom Keeler
Feb 51 min read
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difference between linear and exponential growth
Linear growth adds a fixed amount for each additional unit of input. For example, $5 for each additional hour of work. Exponential...
Tom Keeler
Feb 31 min read
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The hungry box of candy
Ask your 7th grader to tell you a story in which the value of a variable is negative. The story we were telling today is of the box of...
Tom Keeler
Jan 301 min read
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Powers of two to memorize
Memorize 2 to the fifth is 32. Then, you can figure out 2 to the sixth by doubling 32 and 2 to the fourth by halving 32. Similarly,...
Tom Keeler
Jan 301 min read
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The best first move
What is the best first move with the equation 10-4x = 2x+3 ? Many students will choose to subtract 2x from both sides. But then you...
Tom Keeler
Jan 291 min read
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A penny doubled every day for a month or a million dollars
Any reasonable person would take a million dollars, right? How much money is a penny doubled every day for a month? 1 cent, 2 cents, 4...
Tom Keeler
Jan 291 min read
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One half of x
If half of x equals 10, what does x equal? 20 If one third of x equals 10, what does x equal? 30 If two thirds of x equals 10, what does...
Tom Keeler
Jan 281 min read
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Best point to check for an inequality
You have an inequality such as y < 2x+1. What is the best point to check to decide whether the solution is above the line or below the...
Tom Keeler
Jan 281 min read
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Price per piece and delivery charge from a table
7th graders started working on this recently. 8th graders began the year with this. The story is you order candy to be delivered. Candy...
Tom Keeler
Jan 231 min read
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The best point to check (inequalities)
What is the best point to check to decide whether to fill in to the left or right of the solution point? For example, if I have to make...
Tom Keeler
Jan 231 min read
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Proportional vs Non-Proportional
When is something proportional? This is a little more complicated than it seems. I get paid $10/hr for babysitting. The amount of money...
Tom Keeler
Jan 161 min read
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