From the 4 boxes, Nori had 8 * 4 = <<8*4=32>>32 crayons
After giving 5 crayons to Mae, she had 32 - 5 = <<32-5=27>>27 crayons left.
If she only has 15 crayons now, this means she gave Lea 27 - 15 = <<27-15=12>>12 crayons.
Hence, Lea has 12 - 5 = <<12-5=7>>7 more crayons than Mae.
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