计算9+1639×4+8+1639×5+7+1639×6+6+1639×7+5+1639×8+4+1639×9．-数学

题目简介

计算9+

×4+8+

×5+7+

×6+6+

×7+5+

×8+4+

×9．

题型：解答题难度：中档来源：不详

9+class="stub"16

×4+8+class="stub"16

×5+7+class="stub"16

×6+6+class="stub"16

×7+5+class="stub"16

×8+4+class="stub"16

×9
=（9+8+7+6+5+4）+（class="stub"16

×4+class="stub"16

×5+class="stub"16

×6+class="stub"16

×7+class="stub"16

×8+class="stub"16

×9，
=（9+8+7+6+5+4）+class="stub"16

×(9+8+7+6+5+4），
=（9+8+7+6+5+4）×（1+class="stub"16

），
=39×class="stub"55

，
=55．