Calculator for pad+

I tried all calculators on the market and had various problems. We made a calculator that might be easier to use. The main features are as follows:
1. No ads, no ads will be added in the future
2. Support simple calculation and scientific calculation
3. Calculation steps and calculation process can be viewed
4.Support Chinese uppercase display
5. Optimized for Pad high resolution
6. Very small size without taking up storage space
Subscription instructions:
—1 subscription option to choose from. Our standard subscription options are:
Subscribe for1week /1month/1year
—The subscription fee will be paid through the credit card attached to your iTunes account.
-Unless your subscription is cancelled at least 24 hours before the end of the current period, your subscription will be automatically renewed.
—You can manage your subscriptions on your account. You can cancel your subscription or trial at any time by going to the iTunes account settings and canceling the subscription, otherwise it will automatically renew.
—The account will be charged for renewal within 24 hours before the end of the current period, and you will not be able to cancel the subscription within the validity period.
—When purchasing a premium subscription during the free trial period, any unused portion of the free trial period (if provided) will be confiscated.
—For more information, please refer to our "Privacy Agreement" and "Member Service Agreement"
"Privacy Agreement" https://www.jianshu.com/p/3ce508010a23
"Member Service Agreement" https://www.jianshu.com/p/40d4f8cf7b90