Q&A for How to Estimate Fractions

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  • Question
    I have 5 5/8 cups of flour and my sister has 1 1/3 cups of flour to make a cake. How do I estimate how many cups of flour there are in all?
    Donagan
    Top Answerer
    A quick way of doing this is to recognize that 5-5/8 is slightly more than 5½, and 1-1/3 is slightly less than 1½. So if you add 5½ to 1½, you'll get a close estimation of 5-5/8 plus 1-1/3. 5½ + 1½ = 7 cups. (The actual amount is 5-5/8 + 1-1/3 = 5-15/24 + 1-8/24 = 6-23/24.)
  • Question
    How can I estimate 12 3/11 divided by 2 7/12?
    Orangejews
    Community Answer
    Start low by rounding 12 3/11 down to 12 and 2 7/12 up to 3. 12/3 =4. That's a low estimate and a pretty bad one. How about the other direction. Round number up to 12 1/2 and denominator down to 2 1/2. 12.5/2.5 = 5. We now know for certain the quotient is between 4 and 5, and informally suspect it's a lot closer to 5 since that was the better estimate.
  • Question
    How do I simplify 943/2865?
    Cluster_Ducky
    Community Answer
    It is already simplified. The numerator and denominator cannot be simplified any further.
  • Question
    How can I estimate 11 1/2 + 12 3/4?
    Donagan
    Top Answerer
    The fastest way is to round 11½ down to 11, and round 12¾ up to 13, then add 11 plus 13.
  • Question
    How do I estimate 4 2/5 - 1 7/9?
    I_l1ke_gam3s
    Community Answer
    2/5 is less than 1/2, so put that to 4, and 7/9 is greater than 1/2, so round up to 2. 4-2 = 2. Your final approximated answer is 2.
  • Question
    If you estimate 3.2 x 4.9, how much do you get?
    Community Answer
    If you round 3.2 down to 3 and 4.9 up to 5, you would then multiply 3 by 5 to get 15.
  • Question
    How do I multiply fractions and whole numbers?
    I_l1ke_gam3s
    Community Answer
    To multiply a fraction by a whole number, multiply the numerator by the whole number and keep the denominator the same. For example, for 81 x 1/9, you multiply the numerator (1) by 81 to get 81/9, which simplifies to 9.
  • Question
    How do I estimate 9 - 5 1/6?
    I_l1ke_gam3s
    Community Answer
    Since 1/6 is less than 1/2 (1/2 is equal to 3/6), round it down to 5. Then, 9 - 5 = 4.
  • Question
    How can I estimate 27 x 1/7?
    Community Answer
    Recognize that (28)(1/7) = 4. So (27)(1/7) would be a bit less than 4, perhaps between 3.8 and 3.9.
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