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What is the meaning of "Lachshov Machashavos"?
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Rashi and Ramban (in Terumah): It means to weave in expert fashion - different patterns on the two sides of the fabric.
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2.
Targum Onkelos: It means to teach the craftsmen.
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Targum Yonasan: It means "to figure out in his mind how to work in gold, silver and copper ... ".
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In Vayakhel, 35:32 & 34, Targum Yonasan translates the same words like Targum Onkelos here. Refer to 31:4:1:1.
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See also Na'ar Yonasan.