口算 4× 7 16 =	4 5 × 3 4 =	4 21 × 7 16 =	5 9 - 4 11 =	5 9 ×5=
1 5 12 - 7 8 =	5 7 ×2.1=	1 1 3 ×0.12=	1 1 2 × 1 3 =	1 2 + 2 3 =
7-1 10 17 =	（ 3 4 +0.25）×10=	18× 1 3 =	1 1 6 - 5 12 =	0 . 125 × 1 1 2 × 8 =
0 . 125 × 2 7 × 8 =	2 . 5 + 1 1 10 =	1 4 9 × 1 . 8 =	3 4 + 0 . 25 =	5 6 × 1 . 2 =