Evaluate the expression using mental math. Justify each of your steps.
1) 4(19)(-25)
2) 17+32+23
Round: 4*20 is about 80, which multiplied by (20+5)=1600+400=2000 about, and it is negative.
That is mental math.
Thanks
and I just saw a shortcut.
take the 4 and 25 first, 100. then times 19, ....
The problem with mental math is we see things with differing mental processes and perspectives, at differing times.
32+16+8. Evalute the expression justify each of ur steps
5ab
(d+a)^2
When d = -11 and a =17
To evaluate the expression using mental math, we can break down each step and simplify as we go. Here's how:
1) 4(19)(-25)
Step 1: Multiply 4 by 19.
4 * 19 = 76
Step 2: Multiply the result from Step 1 by -25.
76 * -25 = -1900
Justification:
In Step 1, we multiply 4 by 19 because multiplication should be done before any addition or subtraction. This follows the order of operations (PEMDAS/BODMAS), where multiplication comes before addition or subtraction.
In Step 2, we multiply the result from Step 1 by -25 because there is a multiplication instruction preceding it. When multiplying a positive number by a negative number, the result is negative.
2) 17 + 32 + 23
Step 1: Add 17 and 32.
17 + 32 = 49
Step 2: Add the result from Step 1 to 23.
49 + 23 = 72
Justification:
In both steps, we add the numbers together because there are no multiplication or division operations present. Addition and subtraction are performed from left to right, so we start by adding the numbers from left to right.
By following these steps, we can evaluate the expressions using mental math and provide a justification for each step.