91Ó°ÊÓ

Subtracting Integers State the rule for subtracting integers.

Any nonzero real number divided by itself is 1 .

Trail Elevation The North Kaibab Trail in the Grand Canyon descends 439 meters from the North Kaibab trailhead to the Supai Tunnel. The trail continues on to Roaring Springs, which is 921 meters lower than the North Kaibab trailhead, and then descends another 457 meters to Ribbon Falls. How much lower than the Supai Tunnel is Ribbon Falls?

Error Analysis Describe and correct the error. $$ \begin{aligned} -9+\frac{9+20}{3(5)}-(-3) &=-9+\frac{9}{3}+\frac{20}{5}-(-3) \\ &=-9+3+4-(-3) \\ &=1 \end{aligned} $$

Multiplying Decimals When you multiply two decimals, how do you determine where to place the decimal point in the product?

\(-2(6)(-2)(-1)\)