The action research attempted to find out the effect of Math Window Cards as fool in improving the arithmetic skills of grade 3 non-numerates pupils after the 12 weeks of intervention implementation. The Math Window Cards were the primary intervention tools of the researcher to deliberate intervention design to improve the arithmetic skills of the enrolled non-numerates pupils who were struggling in doing simple arithmetic. The indicator on the combined average scores of Math Window Cards I, classified into 5 stages as Advanced Proficient scored berween 81-100. Proficient scored between 61-80, Developing scored berween 41-60, Beginner scored between 21-40 and Non-numerates - scored between 0-20 in
100-item assessment. The gathered data from the reports of Balingasa Elementary School to the Schools Division Office of Ouezon City on School-based Numeracy Assessment for school
year 2019-2020 and Online Numeracy Assessment Result in October 2020 were used.
Descriptive statistics of mean was used by comparing the percentages of mean in pre-test and
post-test. The significant mean difference percentage was 52.74% after the 12 weeks
implementation of the action research interventions. The use of Math Window Cards as
intervention tool in improving the arithmetic skills of grade 3 non-numerates pupils was found
effective by 86% of the respondents. The result showed that learners performed better and
attained mastery in arithmetic when learners are actively engaged, enjoyed and manipulated
concrete indigenous examples. The action research interventions were worthy to be replicated
and recommended for further study. Teachers should take into consideration on the least
learned facts in order for the pupils to master them, then established rapport to pupils and
partnership with parents.

Keyword: arithmetic, Math Window Cards, non-numerates, mathematics & tools