Free Screening Test Whilst this does not provide a formal diagnosis it can start a conversation.
Quote from the link above: there is a consensus that dyscalculia involves difficulties with:
Number sense (an intuitive feel for numbers).
Memorisation and recall of facts that relate to arithmetic.
Calculation.
Mathematical reasoning: figuring out number related information.
Processing numerical information.
Understanding number in written and numerical form.
Basic mental arithmetic: addition, subtraction, division and multiplication.
Basic arithmetic with use of a pen and paper: addition, subtraction, division and multiplication.
Solving real world problems presented in written form.
Handling money and change.
A lack of fluency (speed) when processing number.
Number difficulties affect academic attainment and everyday life.
The big idea: to go back to the beginning and reprogram your brain.
To locate: Anthony Harradine's online learning.
Mangahigh and Sumdog might be worth investigating.
Tiny Polkadot Card Game