①2.1x﹣x=0.77
②
③0.2a+0.2=3
④8x=19
+=
-=
+-=
1-=
+0.625=
6÷25=
3--=
①53+x=89
②3x+5x=12.8
③2x-6.2=2.18
④5×1.4+4x=27
⑤7x-16×4=27
⑥2.8x-1.9x=13.5
①612÷18+780÷30
②2.5×32×12.5
③5÷(0.5+)×
④
⑤()
⑥16×+8×+12÷25