### Home > MC1 > Chapter 9 > Lesson 9.3.1 > Problem9-127

9-127.

Without a calculator, simplify each of the following expressions.

1. $0.25 + 2.5 + 2.5$

Try doing this one without making any calculations on paper. What is $2.5 + 2.5$?

2. $432.7 - 0.08$

Here, you are subtracting $\frac{8}{100} \text{ from }432\frac{70}{100}.$

Which are like parts?
Can you find the difference in your head?

$432.62$

3. $4.57 · 0.3$

It might be useful to think of this as $\left(4\frac{57}{100}\right)\left(\frac{3}{10}\right)\text{ or }\left(\frac{457}{100}\right)\left(\frac{3}{10}\right)$

$\frac{(457)(3)}{1000}=\frac{1371}{1000}=1\frac{371}{1000}=1.371$