Question

Ursula wrote the sum 5.815 +6.021 as a sum of two mixed numbers.
What a sum did she write?
Compare the sum of the mixed numbers to the sum of the decimals

Answer 1

5 $\frac{815}{1000}$  + 6$\frac{21}{1000}$

The sum of these two mixed numbers is 11.836  or 11$\frac{836}{1000}$
Reducing the fraction we get 11 $\frac{209}{250}$ in lowest terms.
(I divided the numerator and denominator by 4).

Answer 2

Part a) sum of the mixed numbers
we know that
$(5.815 +6.021)=(5+0.815)+(6+0.021) \\ \\ =(5+ \frac{815}{1000})+(6+ \frac{21}{1000} ) \\ \\ =(5 \frac{815}{1000} +6 \frac{21}{1000} ) \\ \\ = 11 \frac{836}{1000}$
Reducing the fraction (divided the numerator and denominator by $4$) 

we get

$11 \frac{209}{250}$

Part b) sum of the decimals
we know that
$(5.815 +6.021)=(11.836)$

Part c) Compare the sum of the mixed numbers to the sum of the decimals 

sum of the mixed numbers is equal to  $11 \frac{209}{250}$

sum of the decimals is equal to $11.836$

therefore

$11 \frac{209}{250}=11.836$

$\frac{209}{250} =0.836$