Which is the best estimate of 90 sevenths divided by 1 3 fourths ?

Convert the mixed number: 1 3/4 = 7/4. Then (90/7) ÷ (7/4) = (90/7) × (4/7) = 360/49, which is about 7.3. Of the choices, 6 is closest to 7.3, so the best estimate is 6.

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