Transcript “We cannot hold a torch to light another`s path without brightening

“We cannot hold a torch to light another’s path without
brightening our own.” –
Ben Sweetland
Check homework
Odds w/book
Evens with a neighbor
Sections 2.1 – 2.4
No more than 5 minutes!
Warm-up
2.5 Multiplication of Integers
Properties of Multiplication
a*b=b*a
The order of 2 numbers being multiplied does
not matter.
1*a=a
The product of one & a number is that number.
0*a=0
The product of zero & a number is zero.
-1 * a = -a
The product of a number and -1 is the opposite
of that number.
a * -b = -ab
The product of a and –b is the opposite of ab.
Multiplying 2 numbers with different signs is
ALWAYS a negative answer.
-a * - b = ab
The product of –a and –b is ab. Multiplying 2
numbers with the same sign is ALWAYS a
positive answer.
examples
1.
2.
3.
4.
5.
6.
-3 * -2 * -4 =
-4 * x * -12 =
(-x)3 =
(-x)2 =
(-2)4 =
-24 =
Sect. 7 – Division of Real #
• The integer rules for division are the
same as for multiplication.
• Same signs = positive answer
-20/-4 = 5
• Different signs = negative answer
-20/4 = -5
• Division can be written as multiplication.
• Reciprocals – numbers when multiplied
together equal 1 (excluding 1 * 1)
– Reciprocal of a/b is b/a
– Reciprocal of 4 is ¼
• Division w/reciprocals
– To divide “a” by “b”, you can multiply by the
reciprocal of “b” and get the same answer.
– 20/4 is the same as 20 * 1/4
Write the division as multiplication & solve
3/5 divided by 2 =
3/5 * ½ =
3/10
3x divided by 1/3 =
3x * 3 =
9x
-x / (-6) =
-x * (-1/6) = x/6
Simplifying a quotient
Change to multiplication (32x – 8)/4 =
(32x – 8) ¼ =
¼(32x) – ¼(8) =
8x – 2
(32x – 8)/4 = (another easy way)
32x/4 – 8/4 =
8x - 2
Try these
6/7 divided by 3 =
6/21
4x divided by 3 =
4x/3
(12x + 28)/4 =
3x + 7
Questions?
• Mid-chp quiz tomorrow
• Need to see some of you