Natalie sawed five boards of equal length to make a stool. Each was 9 tenths of a meter long. What is the total length of the boards she sawed? Express your answer as the sum of a whole number and the remaining fractional units.

total length = 4 ¹/₂ meters

Step-by-step explanation:

If each board had 9/10 of a meter long (0,9 m or 90 cm long), the total length of the boards was the sum of all each board's length, that is 5 times 9/10 of a meter. Mathematically

total length = 5 boards * 9/10 meters/board = 5*9/10 meters = 45/10 meters

45/10 meters can be simplified dividing by the common factor 5

45/10 = (9*5) / (2*5) = 9/2

then dividing 9 over 2 → equals 4 with rest = 1 (that is 9 = 4*2 + 1)

therefore

9/2 = 4 ¹/₂, 4=result of division, 1 = rest, 2=denominator of the fraction

total length=9/2 meters = 4 ¹/₂ meters