Describe two different ways that you could find the product 4 × 998 using mental math. Find the product and complete the explanation of why your model works. (1) Think of 998 as 1,000 − 2. So, 4 ×
= 4(1,000 − 2). By the
(select)
Property, 4(1,000 − 2) = 4,000 − 8 =
.

(2) Think of 998 as 900 + 90 +
. By the
(select)
Property, 4(900 + 90 + 8) = 3,600 + 360 +
=
.

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

Factor the following expression. 27y3 – 343 a. (3y + 7)(9y2 + 2ly + 49) b. (3y – 7)(9y2 + 2ly + 49) c. (3y – 7)(932 – 217 + 49) d. (3y + 7)(92 – 2ly + 49)

Kevin's bank offered him a 4.5% interest rate for his mortgage. if he purchases 3 points, what will be his new rate?