A bird eats 7 berries a day. Samuel has 5 birds. How many berries do Samuel's birds eat in 4 days? Think carefully first, then make a decision:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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A bird eats 7 x 4 = 28 berries in 4 days. So, 5 birds can eat 28 x 5 = 140 berries in 4 days. So, the answer is 140.