Question

Find the actual sum of 1 3/4 + 1 5/8 to determine how much David grew in two years. Explain how you know your answer is reasonable

Answer 1

`3(3)/(8)`

Explanation:

Find the sum

`1(3)/(4) +1(5)/(8)`

we know that

`(3)/(4)=(6)/(8)`

substitute

`1(6)/(8) +1(5)/(8)`

step 1

Separate the mixed number into a whole number and a fraction number

`1+(6)/(8) +1+(5)/(8)`

step 2

Group the whole numbers an the fraction numbers

`(1+1)+((6)/(8) +(5)/(8))`

step 3

Combine like terms

`(2)+((11)/(8))`

Remember that

`(11)/(8)=(8)/(8)+(3)/(8)=1+(3)/(8)`

substitute

`2+1+(3)/(8)`

`3+(3)/(8)=3(3)/(8)`

The answer is reasonable

Because

I know that 1 3/4 < 2 and 1 5/8 < 2

so

The sum of both numbers must be less than 4