Identify and explain the subtraction errors.

King Alfred is confused because he is struggling to subtract his accounts.
Below are some of the methods he has used, however he has made several mistakes.

Can you spot the error in his methods?
Explain how he might have made the error.
Solve the calculation (in your books) and share what you did differently.

 

photo 1

photo 3

photo 2

 

Key vocabulary:
exchange   place value    column     subtraction
          carrying over     because    incorrect

 

15 thoughts on “Identify and explain the subtraction errors.

  1. In the first sum when you exchange amount from 7 you should cancel 7 and write 6 on the top of it and then you have to take 5 away from 6 not 60. When you can’t take away 1 from 0, you have to cancel 1 and write 10 on the top of 0.

  2. The correct answer of the first sum
    1072-156=916.

    The correct answer of the second sum
    1432-521=911

    The correct answer of the final sum
    3721-1562=2159

  3. Subtracting sums:

    King alfred should of looked at each sum, and start from the right taking each number of the column and carry it over until it can be subtracted. if yes, you stop and can now work out the answer.

    Answer for sum 1: 916
    Answer for sum 2: 911
    Answer for Sum 3: 2159

  4. 1.K A forget to exchange for the Hundreds column. So the answer should be 916.
    2. K A forgot to exchange for the Tens and Hundreds column. So the answer should be 911.
    3. K A forgot to exchange from the Tens and Hundreds . So the answer should be 2159.

  5. 1. The mistake was that you should have exchanged the hundreds colemn.
    2. The mistake was that he carried over a one and he borrowed a hundred when you can already takeaway three from tow witc is one.
    3.The mistake was he carried over two digits.

  6. 1. The answer is 916 and the answer is wrong because the answer is bigger than the 1072 they added your supposed to subtract. Also he didint exchange the thousand but he did get ones and tens coloum right.
    2. They got it wrong because if you exchange 1 you cross out the 400 and 1000 they did that right but 13 instead of 400 it should be 1400 instead. So the answer is 911. They got the answer right but not the working out for number 2.

  7. 1. He exchanged from 0 when you can’t do that because 0 has no value so you can’t exchange. Also you hd to carry the 1000 to the hundreds because the 0 has nothing to subtract. So he is incorrect.

  8. Number one is wrong because Bob took away the zero But you have exchange and place the one in the hundred column. By Moman and Abdas🌟🌟

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