Posted by **Janae** on Wednesday, October 13, 2010 at 2:20pm.

Evaluate the expression using mental math. Justify each of your steps.

1) 4(19)(-25)

2) 17+32+23

- Math -
**bobpursley**, Wednesday, October 13, 2010 at 2:46pm
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**, Wednesday, October 13, 2010 at 2:54pm
Thanks

- Math -
**bobpursley**, Wednesday, October 13, 2010 at 2:56pm
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**, Tuesday, September 18, 2012 at 6:55pm
32+16+8. Evalute the expression justify each of ur steps

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