直接写得数。3.14×8=31.4÷3.14=16×3.14=12.56÷3.14=3.14×64=100.48÷3.14=60×3.14=3.14×202=

$\text{[math]}$	$\text{[math]}$	$\text{[math]}$
$\text{[math]}$	$\text{[math]}$	$\text{[math]}$

口算与估算未知容易

$\text{[math]}$ ＋ $\text{[math]}$ =	$\text{[math]}$ － $\text{[math]}$ =	$\text{[math]}$ ＋ $\text{[math]}$ =	$\text{[math]}$ － $\text{[math]}$ =
$\text{[math]}$ × $\text{[math]}$ =	$\text{[math]}$ × $\text{[math]}$ =	$\text{[math]}$ ×2=	$\text{[math]}$ ×13=

口算与估算未知容易

口算与估算未知容易

$\text{[math]}$ + $\text{[math]}$ = 1- $\text{[math]}$ = $\text{[math]}$ - $\text{[math]}$ = 2+ $\text{[math]}$ =

$\text{[math]}$ + $\text{[math]}$ = $\text{[math]}$ - $\text{[math]}$ = $\text{[math]}$ + $\text{[math]}$ = $\text{[math]}$ - $\text{[math]}$ =

口算与估算常考题普通

①1- $\text{[math]}$ =	②0.4+ $\text{[math]}$ =	③ $\text{[math]}$	④ $\text{[math]}$
⑤ $\text{[math]}$	⑥ $\text{[math]}$	⑦ $\text{[math]}$	⑧15÷ $\text{[math]}$ =