To cancel your subscription, follow the instructions below:
From your Kindle device access your Appstore Library, see screenshot below.
On the relevant Doodle subscription click on Manage
Untick auto-renew and click Save.
Alternatively, you can click this link to find detailed descriptions on how to cancel your subscription, via all Amazon devices.
Note: Doodle(Maths/English) does not have the ability to manage subscriptions that are processed through Amazon.