{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":42850,"title":"Sum two real numbers","description":"It seems easy, but...\r\n\r\nYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.","description_html":"\u003cp\u003eIt seems easy, but...\u003c/p\u003e\u003cp\u003eYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.\u003c/p\u003e","function_template":"function z = operation(x,y)\r\n  z = x+y;\r\nend","test_suite":"%%\r\nx = 1;\r\ny = 2;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = 2;\r\ny = pi;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = -sqrt(13);\r\ny = 0.25;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = 31/8/87;\r\ny = 22/8/83;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')","published":true,"deleted":false,"likes_count":3,"comments_count":0,"created_by":12767,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":52,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-05-05T15:54:37.000Z","updated_at":"2026-04-27T15:17:52.000Z","published_at":"2016-05-05T15:54:37.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIt seems easy, but...\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":42850,"title":"Sum two real numbers","description":"It seems easy, but...\r\n\r\nYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.","description_html":"\u003cp\u003eIt seems easy, but...\u003c/p\u003e\u003cp\u003eYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.\u003c/p\u003e","function_template":"function z = operation(x,y)\r\n  z = x+y;\r\nend","test_suite":"%%\r\nx = 1;\r\ny = 2;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = 2;\r\ny = pi;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = -sqrt(13);\r\ny = 0.25;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')\r\n\r\n%%\r\nx = 31/8/87;\r\ny = 22/8/83;\r\n\r\nassert(abs(operation(x,y)/(x+y)-1)\u003c1e-11)\r\nfiletext = fileread('operation.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * not allowed')\r\nassert(isempty(strfind(filetext, 'prod')),'prod not allowed')\r\nassert(isempty(strfind(filetext, 'times')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'cross')),'times not allowed')\r\nassert(isempty(strfind(filetext, 'dot')),'times not allowed')\r\nassert(isempty(strfind(filetext, '+')),'sign + not allowed')\r\nassert(isempty(strfind(filetext, '-')),'sign - not allowed')\r\nassert(isempty(strfind(filetext, 'sum')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'add')),'sum not allowed')\r\nassert(isempty(strfind(filetext, 'diff')),'diff not allowed')\r\nassert(isempty(strfind(filetext, 'minus')),'minus not allowed')\r\nassert(isempty(strfind(filetext, 'plus')),'plus not allowed')\r\nassert(isempty(strfind(filetext, 'sign')),'sign not allowed')\r\nassert(isempty(strfind(filetext, 'abs')),'abs not allowed')\r\nassert(isempty(strfind(filetext, '''')),'strings are not allowed')","published":true,"deleted":false,"likes_count":3,"comments_count":0,"created_by":12767,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":52,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-05-05T15:54:37.000Z","updated_at":"2026-04-27T15:17:52.000Z","published_at":"2016-05-05T15:54:37.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIt seems easy, but...\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eYou cannot use +, -, plus, diff, cumsum, *, prod, times, etc.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"restriction\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}