The estimation method is the third grade of primary school.
& ltp & gt& ltimg src = " 80 168 1880 14 "/>& lt/p & gt; & ltp & gt& ltimg src = " 80 168 1880 18 "/>& lt/p & gt; & ltp & gt& ltimg src = " 80 168 188024 "/>& lt/p & gt; & ltp & gt& ltimg src = " 80 168 188027 "/>& lt/p & gt; & ltp> Primary school students who can't learn the estimation method in the third grade can come and see and listen to your words, which is better than studying for ten years. & lt/p & gt; & ltp> 1, rounding method