sum to n terms 项和

n-sum 若剩余值

modulo-N sum N模数和

Riemann n sum 黎曼和

in n sum 总而言之

pollen n sum 花粉统计

sum to n terms n 项和

n term sum n项和数

sum of preceding n terms 前n项和

connected sum of n-manifolds n维流形的连通和