开根号，即求一个数的平方根，具体计算方法如下：
手动计算方法：
1. 估算：根据数字的大小，估算一个大概的平方根值。例如，要计算√25，你可以知道5的平方是25。
2. 试除法：从估算的值开始，逐步尝试更精确的值。例如，对于√25，你可以从5开始，尝试4.9、4.95等，直到找到最接近的平方根。
3. 连续除法：对于更复杂的数字，你可以使用连续除法。例如，要计算√18，你可以这样操作：
18 ÷ 2 = 9
9 ÷ 3 = 3
3 ÷ 3 = 1
1 ÷ 2 = 0.5
0.5 ÷ 2 = 0.25
0.25 ÷ 2 = 0.125
0.125 ÷ 2 = 0.0625
0.0625 ÷ 2 = 0.03125
0.03125 ÷ 2 = 0.015625
0.015625 ÷ 2 = 0.0078125
0.0078125 ÷ 2 = 0.00390625
0.00390625 ÷ 2 = 0.001953125
0.001953125 ÷ 2 = 0.0009765625
0.0009765625 ÷ 2 = 0.00048828125
0.00048828125 ÷ 2 = 0.000244140625
0.000244140625 ÷ 2 = 0.0001220703125
0.0001220703125 ÷ 2 = 0.00006103515625
0.00006103515625 ÷ 2 = 0.000030517578125
0.000030517578125 ÷ 2 = 0.0000152587890625
0.0000152587890625 ÷ 2 = 0.00000762939453125
0.00000762939453125 ÷ 2 = 0.000003814697265625
0.000003814697265625 ÷ 2 = 0.0000019073486328125
0.0000019073486328125 ÷ 2 = 0.00000095367431640625
0.00000095367431640625 ÷ 2 = 0.000000476837158203125
0.000000476837158203125 ÷ 2 = 0.0000002384185791015625
0.0000002384185791015625 ÷ 2 = 0.00000011920928955078125
0.00000011920928955078125 ÷ 2 = 0.000000059604644775390625
0.000000059604644775390625 ÷ 2 = 0.0000000298023223876953125
0.0000000298023223876953125 ÷ 2 = 0.00000001490116119384765625
0.00000001490116119384765625 ÷ 2 = 0.000000007450580596923828125
0.000000007450580596923828125 ÷ 2 = 0.0000000037252912984619140625
0.0000000037252912984619140625 ÷ 2 = 0.00000000186264564923095703125
0.00000000186264564923095703125 ÷ 2 = 0.000000000931322824615978515625
0.000000000931322824615978515625 ÷ 2 = 0.0000000004656614123089892578125
0.0000000004656614123089892578125 ÷ 2 = 0.00000000023283070615449462890625
0.00000000023283070615449462890625 ÷ 2 = 0.000000000116415353077247314453125
0.000000000116415353077247314453125 ÷ 2 = 0.0000000000582076765386236572265625
0.0000000000582076765386236572265625 ÷ 2 = 0.00000000002910383826931182861328125
0.00000000002910383826931182861328125 ÷ 2 = 0.000000000014551919134654914306640625
0.000000000014551919134654914306640625 ÷ 2 = 0.0000000000072759595673274571533203125
0.0000000000072759595673274571533203125 ÷ 2 = 0.00000000000363797978366372875766015625
0.00000000000363797978366372875766015625 ÷ 2 = 0.000000000001818990391831864378830078125
0.000000000001818990391831864378830078125 ÷ 2 = 0.0000000000009094951959159321919150390625
0.0000000000009094951959159321919150390625 ÷ 2 = 0.00000000000045474759795796609595751953125
0.00000000000045474759795796609595751953125 ÷ 2 = 0.000000000000227373798978983047979759765625
0.000000000000227373798978983047979759765625 ÷ 2 = 0.0000000000001136868994899915239798798828125
0.0000000000001136868994899915239798798828125 ÷ 2 = 0.00000000000005684344974499576198993994140625
0.00000000000005684344974499576198993994140625 ÷ 2 = 0.000000000000028421724872497880994969970703125
0.000000000000028421724872497880994969970703125 ÷ 2 = 0.0000000000000142108624362489404974849853515625
0.0000000000000142108624362489404974849853515625 ÷ 2 = 0.00000000000000710543121812447024874249267578125
0.00000000000000710543121812447024874249267578125 ÷ 2 = 0.00000000000000355271560906223512437124633790625
0.00000000000000355271560906223512437124633790625 ÷ 2 = 0.000000000000001776357804531117562185623168953125
0.000000000000001776357804531117562185623168953125 ÷ 2 = 0.00000000000000088317890226555878092781158439265625
0.00000000000000088317890226555878092781158439265625 ÷ 2 = 0.000000000000000441589451132779390463905792196328125
0.000000000000000441589451132779390463905792196328125 ÷ 2 = 0.0000000000000002207947255663896952319528960981640625
0.0000000000000002207947255663896952319528960981640625 ÷ 2 = 0.00000000000000011039736278319484761597644804908203125
0.00000000000000011039736278319484761597644804908203125 ÷ 2 = 0.000000000000000055198681391597423807988224024541015625
0.000000000000000055198681391597423807988224024541015625 ÷ 2 = 0.0000000000000000275993406957987119039941120122705078125
0.0000000000000000275993406957987119039941120122705078125 ÷ 2 = 0.00000000000000001379967034789935595199705600613525390625
0.00000000000000001379967034789935595199705600613525390625 ÷ 2 = 0.000000000000000006899835173949677975998528003067626953125
0.000000000000000006899835173949677975998528003067626953125 ÷ 2 = 0.0000000000000000034499175869748389879992645015338134765625
0.0000000000000000034499175869748389879992645015338134765625 ÷ 2 = 0.00000000000000000172458379348741949399993225076690673828125
0.00000000000000000172458379348741949399993225076690673828125 ÷ 2 = 0.000000000000000000862291896743709746999966125383453369140625
0.000000000000000000862291896743709746999966125383453369140625 ÷ 2 = 0.0000000000000000004311459483718548734999830626917266845703125
0.0000000000000000004311459483718548734999830626917266845703125 ÷ 2 = 0.00000000000000000021507297418692743674999153134586334228515625
0.00000000000000000021507297418692743674999153134586334228515625 ÷ 2 = 0.000000000000000000107536487093463718374995765672931671142578125
0.000000000000000000107536487093463718374995765672931671142578125 ÷ 2 = 0.0000000000000000000537682435467318591869978328364658355712890625
0.0000000000000000000537682435467318591869978328364658355712890625 ÷ 2 = 0.00000000000000000002688412177386592959399891641823291778564453125
0.00000000000000000002688412177386592959399891641823291778564453125 ÷ 2 = 0.000000000000000000013442060886932965296998458209116458892822265625
0.000000000000000000013442060886932965296998458209116458892822265625 ÷ 2 = 0.0000000000000000000067210304434664826884992291045582294464111328125
0.0000000000000000000067210304434664826884992291045582294464111328125 ÷ 2 = 0.00000000000000000000336051522173324134424961455227911472320556640625
0.00000000000000000000336051522173324134424961455227911472320556640625 ÷ 2 = 0.000000000000000000001680257610866620672124807276139557361602783203125
0.000000000000000000001680257610866620672124807276139557361602783203125 ÷ 2 = 0.0000000000000000000008401288054333103360624036380697786808013916015625
0.0000000000000000000008401288054333103360624036380697786808013916015625 ÷ 2 = 0.000000000000000000000420064402716655168031201819034839340400695800780625
0.000000000000000000000420064402716655168031201819034839340400695800780625 ÷ 2 = 0.0000000000000000000002100322013583275840156009095179686702003454003903125
0.0000000000000000000002100322013583275840156009095179686702003454003903125 ÷ 2 = 0.00000000000000000000010501610067916379200780045475898433510017220019515625
0.000000000000000000000105016100679163792007800454758984335100172100097578125
0.000000000000
