Sneaky Math

A Graphic Primer with Projects

Cy Tymony

• Editorial: Andrews McMeel Publishing, LLC
• Año: 2014
• ISBN:
  9781449451691
• Categoría: Pedagogía
• Categoría: Enseñanza de matemáticas

" By capitalizing on these real-world applications, Tymony helps conquer much of the fear and dread associated with traditional math lessons."(Booklist) Cy Tymony, author of the best-sellingSneaky Usesseries, brings his unique, fun hands-on learning approach to all things math. Many people fear math and numbers, even Barbie, who famously said "Math class is tough" in her controversial 1992 talking doll version. But in Sneaky Math, Cy Tymony takes tough and turns it into triumph. He shows us how math is all around us through intriguing and easy projects, including twenty pass-along tools to complement math education programs. ?The book is divided into seven sections: ?1. Fundamentals of Numbers and Arithmetic
?2. Algebra Primer
?3. Geometry Primer
?4. Trigonometry Primer
?5. Calculus Primer
?6. Sneaky Math Challenges, Tricks, and Formulas
?7. Resources

POSITIVE AND NEGATIVE NUMBER RULES

∎ Positive and negative numbers and zero are called integers.

On a number line, negative numbers are shown at the left of the zero mark and positive numbers to the right of zero.

∎ Adding and subtracting positive numbers remain positive:

4 – 2 = 2

(except when subtracting a larger number from the first, e.g., 4 – 7)

∎ When adding or subtracting a larger number, the sign of the larger is the sign of the result.

–7 + 1 = –6

∎ With multiplication and division between two numbers, Like Signs = a Positive; Unlike Signs = a Negative.

Like signs = a positive

– ÷ – or – x – or + x + or + ÷ +

ALL EQUAL A POSITIVE NUMBER: No matter how many numbers you are multiplying, an even number of negative (-) numbers gives you a positive result. An odd number of negative (-) numbers gives you a negative answer.

THE RULES

4 – 2 = 2 –7 + 1 = 6 8 – –3 = 11

Double negative—add both numbers as a positive

–2 – 4 = –6

Multiplication and Division

Like signs = a positive	Unlike signs = a negative
– ÷ –	– ÷ +
– x –	– x +
+ x +	+ ÷ –
+ ÷ +	+ x –

Examples

–2 x 2 = –4	–2 x –3 = 6
6 ÷ –2 = –3	4 x 3 = 12
–4 ÷ 2 = –2	6 ÷ –3 = –2
7 x –4 = –28	–8 ÷ –2 = 4

Project—

SNEAKY CUP CALCULATOR

You can make a simple adding device using two rulers or paper strips numbered like a ruler taped to two cups.

What’s Needed

▸ Paper

▸ 2 Rulers (optional)

▸ 2 Paper or Styrofoam cups

▸ Pencil or pen

As shown in FIGURE 1, simply place the rulers or paper strips numbered like a ruler next to each other. Line up a number on the top ruler with the 0 on the bottom one. Following the top number 5, down to the 0, and across to the lower 4 reveals the sum of 9 on the upper ruler. See FIGURE 2.

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