The recipe called for a pound and half of strawberries but you only neede one-third as many blueberries did How do need?

To determine how many blueberries you need if you only need one-third as many blueberries as you do strawberries, you need to divide the amount of strawberries by 3.

Given that the recipe calls for 1 and 1/2 pounds of strawberries (or 1.5 pounds), dividing this by 3 gives:

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1.5 pounds / 3 = 0.5 pounds

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Therefore, you need 0.5 pounds of blueberries.