1. 直接写出得数。(40☆)
$9×5 = $ $62 + 35 = $ $770 - 40 = $ $620 - 310 = $
$27÷3 = $ $75 - 35 = $ $320 - 80 = $ $430 + 310 = $
$7×3 = $ $64 + 36 = $ $460 - 40 = $ $8700 - 3700 = $
$42÷7 = $ $72 - 68 = $ $440 - 90 = $ $600 + 900 = $
$7×9 = $ $42 + 35 = $ $800 - 30 = $ $5600 + 3000 = $
$16÷8 = $ $48 - 29 = $ $520 + 90 = $ $840 - 630 = $
$8×2 = $ $26 + 18 = $ $270 - 90 = $ $400 + 2900 = $
$12÷4 = $ $24 - 19 = $ $810 - 40 = $ $1200 - 800 = $
$6×5 = $ $84 - 50 = $ $50 + 680 = $ $290 + 500 = $
$18÷2 = $ $80 + 17 = $ $450 - 70 = $ $3400 - 3000 = $

45 97 730 310
9 40 240 740
21 100 420 5000
6 4 350 1500
63 77 770 8600
2 19 610 210
16 44 180 3300
3 5 770 400
30 34 730 790
9 97 380 400

2. 先说说运算顺序,再计算。(18☆)
$20×4 + 170$ $(96 - 65)×3$ $241 - 41×2$
$99÷3 + 6$ $99÷(3 + 6)$ $88÷(401 - 393)$

250 93 159
39 11 11

3. 在每组得数大的算式后面画“√”。(6☆)
(1)$3×9 + 4$ $\square$ (2)$92 - 57 + 25$ $\square$ (3)$66÷6 - 3$ $\square$
$3×(9 + 4)$ $\square$ $92 - (57 + 25)$ $\square$ $66÷(6 - 3)$ $\square$

(1)□ (2)√ (3)□
√ □ √