Question

Use the example below to explain where the decimal point should be placed in the product. Next, explain how estimation can be used to check your answer.
Ex: 25.5 x 0.81 =

Answer 1

Answer:

Our estimation was correct. Look below for explanation.

Explanation:

The decimal place should be shifted to 3 places to decimals to the left because 25.5 has been shifted one decimal place to the left and 0.81 has been shifted 2 decimal places to the left.

Now, to check our answer, you can use 3 ways.

1. You can use a calculator.
2. You can use your "Multiplication method for decimals" to solve.
3. You can simplify in fraction form and at last, you can divide the fractions to obtain your answer.

I am going to solve using the option 3.

• => $25.5(0.81)$
• => $\frac{255 ( 81)}{10(100)}$
• => $\frac{51(81)}{10(20)}$
• => $\frac{4131)}{200}$
• => $20.655$

With that, our estimation was correct. The answer has 3 decimal places.

$BrainiacUser1357$