SUMAS

 https://wordwall.net/es/resource/19433336/sumas-y-restar-emparejar/sumas-y-restas

https://wordwall.net/es/resource/4033337/1er-grado-calculo-mental-de-sumas-y-restas

https://clic.xtec.cat/projects/opera/jclic.js/index.html