1. 直接写出得数。
$3.9 + 1.6 =$ $7 - 0.25 =$ $0.74 - 0.33 =$
$40 - 39.08 =$ $95.09 + 4.1 =$ $5.7 + 0.23 =$
$1.2 - 1.1 =$ $1.35 + 6.65 =$ $9.7 - 7 =$
$3.7 + 9.6 =$ $82 - 5.3 =$ $16×60 =$
$720÷60 =$ $48 - 0.5 =$ $8.33 + 6.67 =$
$65 - 3.2 =$ $6 - 1.8 =$ $5.03 + 10.9 =$

$3.9 + 1.6 = 5.5$
$7 - 0.25 = 6.75$
$0.74 - 0.33 = 0.41$
$40 - 39.08 = 0.92$
$95.09 + 4.1 = 99.19$
$5.7 + 0.23 = 5.93$
$1.2 - 1.1 = 0.1$
$1.35 + 6.65 = 8$
$9.7 - 7 = 2.7$
$3.7 + 9.6 = 13.3$
$82 - 5.3 = 76.7$
$16×60 = 960$
$720÷60 = 12$
$48 - 0.5 = 47.5$
$8.33 + 6.67 = 15$
$65 - 3.2 = 61.8$
$6 - 1.8 = 4.2$
$5.03 + 10.9 = 15.93$

2. 计算下列各题，能简算的要简算。
$12 - (3.6 + 7.29)$ $27.18 - 9.1 - 1.9$
$4.37 + 8.5 + 0.63 + 1.5$ $25.28 - 4.72 - 5.28$
$3.27 + 5.49 - 1.27 + 4.51$ $9.75 - (6.75 + 0.4)$
$10.27 - 0.34 + 1.73 - 2.66$ $12.457 - (2.457 - 4.5 - 5.5)$

$12 - (3.6 + 7.29)$
$=12 - 10.89$
$=1.11$
$27.18 - 9.1 - 1.9$
$=27.18 - (9.1 + 1.9)$
$=27.18 - 11$
$=16.18$
$4.37 + 8.5 + 0.63 + 1.5$
$=(4.37 + 0.63) + (8.5 + 1.5)$
$=5 + 10$
$=15$
$25.28 - 4.72 - 5.28$
$=25.28 - 5.28 - 4.72$
$=20 - 4.72$
$=15.28$
$3.27 + 5.49 - 1.27 + 4.51$
$=(3.27 - 1.27) + (5.49 + 4.51)$
$=2 + 10$
$=12$
$9.75 - (6.75 + 0.4)$
$=9.75 - 6.75 - 0.4$
$=3 - 0.4$
$=2.6$
$10.27 - 0.34 + 1.73 - 2.66$
$=(10.27 + 1.73) - (0.34 + 2.66)$
$=12 - 3$
$=9$
$12.457 - (2.457 - 4.5 - 5.5)$
$=12.457 - 2.457 + 4.5 + 5.5$
$=(12.457 - 2.457) + (4.5 + 5.5)$
$=10 + 10$
$=20$