1. Existing tool materials: 10 kg oil barrel, 3 kg empty barrel, 7 kg empty barrel.
2. First, pour the oil into the seven-catty empty barrel and fill it up, that is, there are only three catties of oil left in the ten-catty oil barrel, as shown in the figure.
3. Then fill an empty bucket of three catties from a bucket that can hold seven catties of oil, that is, there are four catties of oil left in the bucket of seven catties, as shown in the figure.
4. Pour the oil from 3kg barrel back to10kg barrel, as shown in the figure.
5. Pour the remaining four catties of oil in the seven catties bucket into the three catties bucket, that is, there is one catty of oil left in the seven catties bucket, as shown in the figure.
6. Then pour the oil from three Jin barrels back to ten Jin barrels, as shown in the figure.
7. Pour the remaining one catty of oil from seven catties of barrels into three catties of barrels, as shown in the figure.
8. Then pour the oil in the ten-Jin barrel into the seven-Jin empty barrel and fill it up, that is, there are two Jin of oil left in the ten-Jin barrel, as shown in the figure.
9. Pour the oil from seven Jin barrels into three Jin barrels and fill them up. Because there is one catty of oil in a three-catty barrel, if you pour in two catties of oil, there are five catties of oil left in a seven-catty barrel, as shown in the figure.
10, and then pour all three Jin barrels of oil into 10 Jin barrel. Because 10 Jin barrel had two Jin of oil left, there were five Jin of oil in ten Jin barrel and five Jin of oil in seven Jin barrel.