幼儿园原有19个皮球，又买了12个皮球，现在幼儿园共有多少个皮球？3X7w:E7P7z0J8`-N7p
算式：提示.a1@+]4x7X*n,U7|+X*Q6Z4G'H'N3X7w:E7P7z0J8`-N7p
答：现在幼儿园共有;m2d4k*W5?6k4d4g-W*Z个皮球。3X7w:E7P7z0J8`-N7p