User talk:2405:204:1407:9551:D5B4:3D99:5327:47D4

January 2020
Hello, I'm DVdm. I wanted to let you know that I reverted one of your recent contributions —specifically this edit to Mental calculation—because it did not appear constructive. If you would like to experiment, please use the sandbox. If you have any questions, you can ask for assistance at the Help desk. Thanks. DVdm (talk) 15:14, 14 January 2020 (UTC)
 * If this is a shared IP address, and you did not make the edits referred to above, consider creating an account for yourself or logging in with an existing account so that you can avoid further irrelevant notices.