11~20各数的认识返回10个一1个十是12121517
161113182个十20是00010120123012340123450123456012345670123456780123456789012345678910012345678910110123456789101112012345678910111213012345678910111213140123456789101112131401234567891011121314150123456789101112131415160123456789101112131415161701234567891011121314151617180123456789101112131415161718190123456789101112131415161718192001234567891011121314151617181920从7数到17从11数到201715和17抢答题:（1）15是由()个十和()个一组成．（2）()个十和()个一组成17．（3）16前面一个数是(),后面一个数是()．（4）与19相邻的两个数是()和()．111518571720再见
