# Words by the Numbers 7, Exercise 1
def flesch_ease(words, sentences, syllables):
    return 206.835 - 1.015 * (words / sentences) - 84.6 * (syllables / words)

# The worked example: 100 words, 5 sentences, 140 syllables
print(f"100 words, 5 sentences, 140 syllables: ease {flesch_ease(100, 5, 140):.1f}")

# A grid: how the score moves with sentence length and word length
print()
print("ease score      " + "".join(f"{spw:>10}" for spw in (1.2, 1.5, 1.8)) + "   (syllables per word)")
for wps in (10, 20, 30):
    row = [206.835 - 1.015 * wps - 84.6 * spw for spw in (1.2, 1.5, 1.8)]
    print(f"{wps:2d} words/sent " + "".join(f"{r:10.1f}" for r in row))

# Solve for the word length that gives ease 60 at 15 words per sentence
target, wps = 60, 15
spw = (206.835 - 1.015 * wps - target) / 84.6
print()
print(f"for ease {target} at {wps} words per sentence you need {spw:.3f} syllables per word")
print(f"check: {206.835 - 1.015 * wps - 84.6 * spw:.1f}")

# One more syllable per 10 words costs how many points?
print(f"adding 0.1 syllables per word changes the score by {-84.6 * 0.1:.2f}")
print(f"adding 1 word to every sentence of 15 changes it by {-1.015:.3f}")

# Output when run (Python 3.14; texts from the Project Gutenberg plain-text files):
# 100 words, 5 sentences, 140 syllables: ease 68.1
#
# ease score             1.2       1.5       1.8   (syllables per word)
# 10 words/sent       95.2      69.8      44.4
# 20 words/sent       85.0      59.6      34.3
# 30 words/sent       74.9      49.5      24.1
#
# for ease 60 at 15 words per sentence you need 1.556 syllables per word
# check: 60.0
# adding 0.1 syllables per word changes the score by -8.46
# adding 1 word to every sentence of 15 changes it by -1.015