```python
def tiles_across(length: int, tile: int) -> int:
    return (length + tile - 1) // tile

def tiles_needed(width: int, height: int, tile: int, spare: int) -> int:
    total_tiles = width * height
    breakage_allowance = total_tiles * spare / 100
    total_tiles += breakage_allowance
    return (total_tiles + tile - 1) // tile
```