1. 直接写出得数。
3x + 5x =
0.3c + 0.5c =
a + 0.1a =
4x + 5x + 6x =
7a + 3a =
3.5a - a =
0.6d × 80d =
3y + 6y - 8y =
5.7y + 0.43y =
4m + 1.3m =
4.5b - 2.3b =
0.48m ÷ 0.12 - 0.48m =
12t - t =
a - 0.2a =
4c + 2.8c =
7n - 3n + 2n =
5a - 4a =
5.5 × 2b =
2.5m - m =
5a - 1.3a - 1.7a =
12x + 13x =
4.8n - 3.8n =
6.5t - 5.5t =
4 + 5y - 2y =
9c + 2c =
3.7x + 1.3x =
9y - 3.5y =
8y × 1.5y ÷ 12 =
9.9c ÷ 0.33 =
0.52 + 1.52 =
0.8k × 12.5k =
4.5y - (3y + 5x) =

8x 0.8c 1.1a 15x 10a 2.5a 48d² y 6.13y 5.3m 2.2b 3.52m 11t 0.8a 6.8c 6n a 11b 1.5m 2a 25x n t 3y+4 11c 5x 5.5y y² 30c 2.04 10k² 1.5y-5x

2. 计算下面各题,能简算的要简算。
7.75 ÷ 1.25 ÷ 0.8
4.8 × 9.9 + 4.8 × 0.1
2.9 + 9.3 ÷ (3.1 × 5)
12.6 × 101 - 12.6
(8.5 - 1.69 ÷ 1.3) × 600
0.648 ÷ [(0.4 + 0.5) × 0.6]

7.75 48 3.5 1260 4320 1.2

7.75 ÷ 1.25 ÷ 0.8
=7.75÷(1.25×0.8)
=7.75÷1
=7.75
4.8 × 9.9 + 4.8 × 0.1
=4.8×(9.9+0.1)
=4.8×10
=48
2.9 + 9.3 ÷ (3.1 × 5)
=2.9+9.3÷15.5
=2.9+0.6
=3.5
12.6 × 101 - 12.6
=12.6×(101-1)
=12.6×100
=1260
(8.5 - 1.69 ÷ 1.3) × 600
=(8.5-1.3)×600
=7.2×600
=4320
0.648 ÷ [(0.4 + 0.5) × 0.6]
=0.648÷(0.9×0.6)
=0.648÷0.54
=1.2

(1)规定 $ m※n = n^2 - m^2 + 2mn $,则 $ 4※5 = $。
(2)规定 $ a\triangle b = (a^2 - 2a) ÷ (3 + b) $,则 $ 6\triangle5 = $。

(1) 49
(2) 3