little friend

plural little friends

1. abacus jargoneducationA natural number which when added to another number equals 5.

   The little friend of 2 is 3 because 2 + 3 = 5.

   1 more example

   In Sessions 6 and 7, the little friends (terminology that refers to the numbers that are missing to reach another number, e.g., the number 1 is missing 4 to reach 5, so 1 is a little friend of 4) were applied in addition to being used when a calculation could not be performed directly because there were not enough pieces in the row to be added. In Sessions 8 and 9, the same little friends were used, but, in this case, when there are not enough pieces in the row to be subtracted.

   2021 February 21, Samuel P. León, María del Carmen Carcelén Fraile, Inmaculada García-Martínez, “Development of Cognitive Abilities through the Abacus in Primary Education Students: A Randomized Controlled Clinical Trial”, in Education Sciences, volume 11, number 2, Basel, Switzerland: MDPI, →DOI, →ISSN, →OCLC

   Synonyms: small friend

2. Used other than figuratively or idiomatically: see little, friend.