Letter change in counting strides

Question

Here is something that has been bothering me for a while now: How to know how the letter changes inside words like for example 一杯、二杯？

More concretely, I really need to know how to correctly count strides. I've heard people say it but I can't make sense of it so I keep forgetting and end up being too embarrassed to make sentences that involve counting strides (of a cantering horse).

I know one is 一歩{いっぽ}　and perhaps 二歩{にほ} but after that I have no clue whatsoever whether it changes to b, p or stays h.

Please could someone teach me the correct way to count strides from 1 to 10?

And, well, it would really help me if you could explain the system to me so that I can reuse it for cups of coffee and whatever else I may be counting in the future and don't have to ask it again here. > . <

Answer 1

Q. Please could someone teach me the correct way to count strides from 1 to 10?

A. As for counting strides/steps here is the list:

1. 一歩{いっぽ} - changes to p
2. 二歩{にほ}
3. 三歩{さんぽ} ** - changes to p
4. 四歩{よんほ}
5. 五歩{ごほ}
6. 六歩{ろっぽ} - changes to p
7. 七歩{ななほ}
8. 八歩{はっぽ} - changes to p
9. 九歩{きゅうほ}
10. 十歩{じゅっぽ} - changes to p

**not to be mixed up with 散歩{さんぽ} meaning "(a) walk"

Here are the counters for cups (of things, like coffee):

1. 一杯{いっぱい} - changes to p
2. 二杯{にはい}
3. 三杯{さんばい} - changes to b
4. 四杯{よんはい}
5. 五杯{ごはい}
6. 六杯{ろっぱい} - changes to p
7. 七杯{ななはい}
8. 八杯{はっぱい} - changes to p
9. 九杯{きゅうはい}
10. 十杯{じゅっぱい} - changes to p