## Tuesday, April 16, 2013

### This Week's Work : Week 5 -- for Inquisitive Young Mathletes

Evan (a 5th grader in PA) 's Problem of the Week:
A man notices a sign in Shop-a-Lot that says: "All prices are marked 25% off today only!" He decides to buy a shirt that costs $65.12 before the discount. He then uses a$16 gift certificate and the clerk applies 12% sales tax. What is the final cost of the shirt after all the steps are applied? Express your answer to the nearest hundredth.

Solution:
When there is a discount that is 25% off, the original price is going to be 75% times the original price. Therefore, 75% of $65.12 is$48.84. Next, subtracting $16, we obtain$32.84. Finally, applying 12% sales tax, we get $32.84 x 112% (since original price is added to the sales tax "price") which is$36.7808. This rounded to the nearest hundredth is \$36.78.

Assignment 1:

Painted Cube Problems

Visualization of the Painted Cube Problems

It's more fun if you dig out Legos or Unit Cubes and just build some cubes (and later rectangular prism)
and spend some time observing how it works.

Assignment 2:

Review special right triangle, Pythagorean triples, theorem :

30-60-90 , 45-45-90 special right triangle angle ratios

Dimensional Change