Posted by Janae on .
Evaluate the expression using mental math. Justify each of your steps.
1) 4(19)(25)
2) 17+32+23

Math 
bobpursley,
Round: 4*20 is about 80, which multiplied by (20+5)=1600+400=2000 about, and it is negative.
That is mental math. 
Math 
Janae,
Thanks

Math 
bobpursley,
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. 
Math 
Alecia,
32+16+8. Evalute the expression justify each of ur steps

Math 
Gloria,
5ab