Really not sure how to go about the two questions here and I have not been able to find something similar like this online. Would appreciate anyones help on how to answer the two questions! Thank you in advance.
How do I add decimal expansions without a calculator
-
0the question tells you to do it by converting the decimals to fractions -- did you try that? – 2017-02-10
-
0yeah I got 64/99 + 94/99 but i`m not sure if thats correct. – 2017-02-10
-
0You can check if 94/99 is the same as.94949494... with the help of your calculator – 2017-02-10
1 Answers
When converting part a) to a fraction, you should get: $$\frac{67}{99}+\frac{94}{99}$$ If you divide by $99$, the digits on the numerator should repeat in the decimal form if the numerator is less than $100$ for positive integers.
Let me demonstrate why: $$\frac{67}{99}=\frac{67}{100}+\frac{67}{9900}=0.67+\frac{67}{9900}$$ We can continue this process: $$\frac{67}{9900}=\frac{67}{10000}+\frac{67}{990000}=0.0067+\frac{67}{990000}$$ $$\frac{67}{990000}=\frac{67}{1000000}+\frac{67}{99000000}=0.000067+\frac{67}{99000000}$$ Repeating this process infinitely gives: $$\frac{67}{99}=0.67+0.0067+0.000067\cdots=0.\dot{6}\dot{7}$$
So, try to convert the decimal forms you have into fractional form, and add the two fractions for part a) and multiply for part b).
If you wish, you can comment the answers you get below and I could verify them.
