13．口算．
0 158916 158924 158930 158934 158940 158942 158946 158952 158954 158960 158966 158970 158972 158976 158982 158984 158990 158994 158996 159000 159002 159006 159008 159010 159011 159012 159014 159015 159016 159018 159020 159024 159026 159030 159032 159036 159042 159044 159050 159054 159056 159060 159066 159072 159074 159080 159084 159086 159092 159096 159102 159110 199269
| 2.2+3.57= | 3.25×4= | 6.75+0.25= | 4÷10= | 17÷1000= |
| 0.63×10= | 0.25×0= | 0.56+0.4= | 1.25×100= | 1-0.93= |