The Coherent Curriculum

San Diego

It is "math choice'' time in Jane Fulkerson's combined kindergarten and 1st-grade class here, and there is an audible buzz in the air.

Children are sprawled around the room as they engage in a wide range of carefully chosen activities. In one corner, tiny hands spin a number on a cardboard spinner and count out colorfully painted beans. On the floor, two small girls connect colored plastic cubes to make patterns repeat. Three children at a table nearby color in rows of seven blocks each on a worksheet.

"You have to make different patterns,'' explains one of the three, a pigtailed girl in a spotless pink sweatsuit. "But...