According to the CCSSM, Kindergarten students should "fluently add and subtract within 5 (K.OA.5)" and "for any number from 1 to 9, find the number that makes 10 when added to the given number (K.OA.4)".
Building strong number sense is one of the most important things elementary school teachers can do to increase math fluency.
Number bonds & pairs help students see that numbers can be "broken" into pieces to make computation easier (decomposing/composing). With number bonds and pairs, student