Answer:
We can use number lines for adding as well as subtracting integers. For doing this:
1. First mark the first integer on the number line.
2. Now to add a positive integer to this number, move to the right on the number line from this number.
3. In case you have to add a negative integer, move to the left on the number line from this number.
4. Subtracting an integer means adding its opposite and hence, if you have to subtract a positive integer from this number, move to the left on the number line from this number.
5. But if you have to subtract a negative integer from this number, move to the right on the number line from this number.
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Each octave in the piano is composed of 8 keys with the end key overlapping the next one which means the last key is the first key of the next octave. In 52 white keys, there are 7 octaves which is composed of 43 full keys and 7 overlapping keys. Answer to this problem is 7 octaves.