The source term indicates a fraction a/b, because it contains an ordinal number at the end position, i.e., "fifths" that means here: 1/5 (خُمس in Arabic).
"one hundred thirty" represents 130 (مائة وثلاثون with the Arabic letters).
Mathematically speaking, the source term means 130 multiplied by 1/5, that is to say: 130 * 1/5 = 130 = 26.
Hence, "one hundred thirty fifths" means "مائة وثلاثون خُمسًا" which means 130/5, and that equals 26.

Note: I prefer using مائة instead of مئة, because مائة is the one written in the Quran and printed on our currencies.

For further information, take a look at the following:

1/2 - a half
1/3 - a third
2/3 - two thirds
1/4 - a quarter (a fourth)
3/4 - three quarters (three fourths)
1/5 - a fifth
2/5 - two fifths
1/6 - a sixth
5/6 - five sixths
1/7 - a seventh
1/8 - an eighth
1/10 - a tenth
7/10 - seven tenths
1/20 - a twentieth
47/100 - forty-seven hundredths
1/100 - a hundredth
1/1,000 - a thousandth
Notice that for 1/4, you can say a quarter OR a fourth.


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Note added at 249 days (2021-02-14 11:52:59 GMT)
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I've forgotten to divide 130 by 5 in the following:
Mathematically speaking, the source term means 130 multiplied by 1/5, that is to say: 130 * 1/5 = 130/5 = 26.