Martin had 7 pounds of grapes left and gave away 2/5 of them explain how to use comparable numbers to estimate the amount of grapes he gave away

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Step-by-step explanation:

Compatible numbers are numbers that are easy to use in mental arithmetic.

Martin gave away ⅖ of 7 lb of grapes, so the amount he gave away was

⅖ * 7 lb

⅖ is close to ²/₄ (½), and it is easy to take half of something mentally.

Half of 7 is about 3, so Martin gave away about 3 lb of grapes (the exact answer is 2.8 lb).