【答案】:
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【解析】:
$20 - 8×2 = 20 - 16 = 4$,$(20 - 8)×2 = 12×2 = 24$,$4<24$;
$45÷9 - 4 = 5 - 4 = 1$,$45÷(9 - 4) = 45÷5 = 9$,$1<9$;
$256 - 32 + 68 = 224 + 68 = 292$,$256 - 32 - 68 = 224 - 68 = 156$,$292>156$;
$36÷3÷3 = 12÷3 = 4$,$36÷(3×3) = 36÷9 = 4$,$4 = 4$。
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