Tenths and hundredths, step by step

Three tenths plus four hundredths is thirty-four hundredths.

The question

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same size:100ths
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  1. Tenths and 100ths are different sizes of piece. Two different sizes cannot be counted as one total — that is the whole difficulty here.
  2. Both can be cut into 100ths: 10 goes into 100, and so does 100. So 100 is the size to use.
  3. 6/10 is the same amount as 60/100, and 33/100 is the same amount as 33/100. Nothing has got bigger — the pieces just got smaller and there are more of them.
  4. Now they are the same size, so count them: 60 + 33 = 93, giving 93/100.

How it works.

  1. 01

    Tenths and 100ths are different sizes of piece. Two different sizes cannot be counted as one total — that is the whole difficulty here.

  2. 02

    Both can be cut into 100ths: 10 goes into 100, and so does 100. So 100 is the size to use.

  3. 03

    6/10 is the same amount as 60/100, and 33/100 is the same amount as 33/100. Nothing has got bigger — the pieces just got smaller and there are more of them.

  4. 04

    Now they are the same size, so count them: 60 + 33 = 93, giving 93/100.