grep1-1  Exercise 1: A Word in Any Case, Without the Pies
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cat > inventory.txt <<'EOF'
Apple juice
apple pie
pineapple
green apple
APPLE sauce
crab apples
EOF

# the word apple, any case, not part of a longer word
grep -iw apple inventory.txt

echo ---

# ...and not the pies: the first grep's output is the second grep's input
grep -iw apple inventory.txt | grep -v pie

Output:

Apple juice
apple pie
green apple
APPLE sauce
---
Apple juice
green apple
APPLE sauce

WHY THIS WORKS AS AN ANSWER
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-i makes Apple, apple and APPLE all match; -w refuses pineapple (the letters before 'apple' make it part of a longer word) and crab apples (the 's' after it does).
That leaves four lines. The second command reads the first one's output on its standard input (no file name given) and -v drops the line that mentions pie.
Combining -i and -w in one option group (-iw) is the same as -i -w.