I am based in South Tottenham, N15, and provide maths tuition to an area
extending as far as 5km from my home, give or take.

Since I never miss an opportunity to throw in some maths, this represents
an area given by πr² = π(5²) = 78.5km² (correct to 3 s.f.).

Postcode and area coverage:

N1,N4-10,N13, N15-19,N22,E5,E8-10,E17

Seven Sisters, South Tottenham, Finsbury Park, Manor House, Stroud Green, Shacklewell,
Stamford Hill, Stoke Newington, Tottenham, Tottenham Hale, Crouch End, Hornsey,
Turnpike Lane, Clapton, Hackney Marshes, Lea Bridge, Lower Clapton, Upper Clapton,
Highbury, Alexandra Palace, Bowes Park, Noel Park, Wood Green, Holloway, Lower Holloway,
Archway, Tufnell Park, Upper Holloway, Dartmouth Park, Dalston, Highgate, Lower
Edmonton, Leyton, Higham Hill, Upper Walthamstow, Walthamstow, Angel, Barnsbury,
Canonbury, Clerkenwell, De Beauvoir Town, Hoxton, Pentonville, Shoreditch, Hackney
Wick, Homerton, South Hackney, Victoria Park, Palmers Green, Muswell Hill, Bounds Green,
Edmonton, Upper Edmonton