a + a + a + a + a = ???
answer: 5a
3c + 2c + c = ???
answer: 6c
e2 + 2e2 = ???
answer: 3e2
2a + 3b + 4a + b = ???
answer: 6a + 4b
simplify: 3p + 4z + 2p - z
answer: 5p + 3z
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