17 1/5 + 15 11/20 + 7 4/5

⚠ 17 1/5 is read as the mixed number 17 + 1/5■15 11/20 is read as the mixed number 15 + 11/20■7 4/5 is read as the mixed number 7 + 4/5

Let's evaluate:

17

+ \frac{1}{5}

+ 15

+ \frac{11}{20}

+ 7

+ \frac{4}{5}

ⓘ Start from

17

and move forward

15

on the number line:

17 + 15

32

■Add fractions by using a common denominator and then adding their numerators:

\frac{1}{5} + \frac{11}{20}

\frac{4 + 11}{20}

32

+ \frac{4 + 11}{20}

+ 7

+ \frac{4}{5}

ⓘ Calculate the numerator and denominator before dividing:

4 + 11

15

32

+ \frac{15}{20}

+ 7

+ \frac{4}{5}

ⓘ Start from

32

and move forward

7

on the number line:

32 + 7

39

■We simplify the fraction by dividing the numerator and the denominator by

5

, their greatest common divisor:

\frac{15}{20}

\frac{3 \times 5}{4 \times 5}

\frac{3}{4}

39 + \frac{3}{4} + \frac{4}{5}

ⓘ Add fractions by using a common denominator and then adding their numerators. We choose

20

, the least common multiple of

4

and

5

. Multiplying the numerator and the denominator by the same number does not change the fraction:

\frac{3}{4} + \frac{4}{5}

\frac{3 \times 5}{4 \times 5} + \frac{4 \times 4}{5 \times 4}

\frac{3 \times 5 + 4 \times 4}{4 \times 5}

39 + \frac{3 \times 5 + 4 \times 4}{4 \times 5}

ⓘ Multiplications are done before additions and subtractions:

3 \times 5

15

4 \times 4

16

ⅰ

4 \times 5

20

39 + \frac{15 + 16}{20}

ⓘ Calculate the numerator and denominator before dividing:

15 + 16

31

39 + \frac{31}{20}

▶Result:

40

\frac{11}{20}

ⓘ Since the fraction

\frac{31}{20}

exceeds 1, take

1

out of it and add it to the whole part:

39 + \frac{31}{20}

39 + \frac{20 + 11}{20}

39 + \frac{20}{20} + \frac{11}{20}

39 + 1 + \frac{11}{20}

40 + \frac{11}{20}

The numeric value of:

40 + \frac{11}{20}

is:

40 + 0.55

▷

40.55

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