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Continue to ChatCÁLCULO MENTAL: Estrategia para sumar 9, 19, 29, etc. https://www.recursosep.com/2018/08/22/calculo-mental-estrategia-para-sumar-9-19-29-etc/
CÁLCULO MENTAL: Estrategia para sumar 9, 19, 29, etc. https://www.recursosep.com/2018/08/22/calculo-mental-estrategia-para-sumar-9-19-29-etc/