### Home > ACC6 > Chapter 4 Unit 4 > Lesson CC1: 4.1.3 > Problem4-35

4-35.

Estimate each sum or difference below by stating which whole numbers the answer should be between. Then check your conclusion by calculating the actual sum or difference.

1. $5.2 - 2.09$

• About how big should their difference be? Estimate by first subtracting $2$ from $5$ and then subtracting $2$ from $6$.

$\quad5.20\\-2.09 \\\quad \overline{3.11}$

1. $25 \frac { 1 } { 3 } - 17 \frac { 5 } { 6 }$

• To estimate the difference, try rounding the first term to $25$ and the second term to $18$.

1. $3 \frac { 3 } { 4 } + 2 \frac { 5 } { 7 }$

• To calculate the sum, you may want to convert these mixed numbers into fractions greater than one before adding.

The answer should be between $6$ and $7$.
How can you tell?

1. $103.57 + 29.6$

• Since each of these have a portion just over one-half, try rounding one up to the nearest whole number and rounding the other one down.