Calculation: ((1986+1985*1987)/(1986*1987-1))+((1987+1986*1988)/(1987*1988-1))+((1988+1987*1989)/(1988* 1989-1))+((1989+1988*1990)/(1989*1990-1))+((1990+1989*1991)/(1990*1991-1))+((1991+1990*1992) /(1991*1992-1))+((1992+1991*1993)/(1992*1993-1)).
计算：((1986+1985*1987)/(1986*1987-1))+((1987+1986*1988)/(1987*1988-1))+((1988+1987*1989)/(1988*1989-1))+((1989+1988*1990)/(1989*1990-1))+((1990+1989*1991)/(1990*1991-1))+((1991+1990*1992)/(1991*1992-1))+((1992+1991*1993)/(1992*1993-1))．
<gadget id="calculator">1_985 * 1_987</gadget>
<output>3_944_195</output>

<gadget id="calculator">1_986 + 3_944_195</gadget>
<output>3_946_181</output>

<gadget id="calculator">1_986 * 1_987</gadget>
<output>3_946_182</output>

<gadget id="calculator">3_946_182 - 1</gadget>
<output>3_946_181</output>

<gadget id="calculator">3_946_181 / 3_946_181</gadget>
<output>1</output>

<gadget id="calculator">1_986 * 1_988</gadget>
<output>3_948_168</output>

<gadget id="calculator">1_987 + 3_948_168</gadget>
<output>3_950_155</output>

<gadget id="calculator">1_987 * 1_988</gadget>
<output>3_950_156</output>

<gadget id="calculator">3_950_156 - 1</gadget>
<output>3_950_155</output>

<gadget id="calculator">3_950_155 / 3_950_155</gadget>
<output>1</output>

<gadget id="calculator">1_987 * 1_989</gadget>
<output>3_952_143</output>

<gadget id="calculator">1_988 + 3_952_143</gadget>
<output>3_954_131</output>

<gadget id="calculator">1_988 * 1_989</gadget>
<output>3_954_132</output>

<gadget id="calculator">3_954_132 - 1</gadget>
<output>3_954_131</output>

<gadget id="calculator">3_954_131 / 3_954_131</gadget>
<output>1</output>

<gadget id="calculator">1_988 * 1_990</gadget>
<output>3_956_120</output>

<gadget id="calculator">1_989 + 3_956_120</gadget>
<output>3_958_109</output>

<gadget id="calculator">1_989 * 1_990</gadget>
<output>3_958_110</output>

<gadget id="calculator">3_958_110 - 1</gadget>
<output>3_958_109</output>

<gadget id="calculator">3_958_109 / 3_958_109</gadget>
<output>1</output>

<gadget id="calculator">1_989 * 1_991</gadget>
<output>3_960_099</output>

<gadget id="calculator">1_990 + 3_960_099</gadget>
<output>3_962_089</output>

<gadget id="calculator">1_990 * 1_991</gadget>
<output>3_962_090</output>

<gadget id="calculator">3_962_090 - 1</gadget>
<output>3_962_089</output>

<gadget id="calculator">3_962_089 / 3_962_089</gadget>
<output>1</output>

<gadget id="calculator">1_990 * 1_992</gadget>
<output>3_964_080</output>

<gadget id="calculator">1_991 + 3_964_080</gadget>
<output>3_966_071</output>

<gadget id="calculator">1_991 * 1_992</gadget>
<output>3_966_072</output>

<gadget id="calculator">3_966_072 - 1</gadget>
<output>3_966_071</output>

<gadget id="calculator">3_966_071 / 3_966_071</gadget>
<output>1</output>

<gadget id="calculator">1_991 * 1_993</gadget>
<output>3_968_063</output>

<gadget id="calculator">1_992 + 3_968_063</gadget>
<output>3_970_055</output>

<gadget id="calculator">1_992 * 1_993</gadget>
<output>3_970_056</output>

<gadget id="calculator">3_970_056 - 1</gadget>
<output>3_970_055</output>

<gadget id="calculator">3_970_055 / 3_970_055</gadget>
<output>1</output>

<gadget id="calculator">1 + 1 + 1 + 1 + 1 + 1 + 1</gadget>
<output>7</output>

<result>7</result>