1. 在○和$□$里填上相应的运算符号和数。
(1)$325 - 89 - 25 = 325 - □ - 89$
(2)$679 - 236 - 164 = □ - (236 ◯ 164)$
(3)$456 - 137 - 163 = □ ◯ (□ ◯ □)$
(4)$733 - (133 + 256) = 733 ◯ 133 ◯ 256$

1. (1)25 (2)679 + (3)456 - 137 + 163 (4)- -

2. 计算下面各题,怎样简便就怎样计算。
$469 - 175 - 169$ $910 - 268 - 232$
$517 - 117 - 58 - 142$ $647 - 85 + 53 - 15$

2. 469 - 175 - 169 = (469 - 169) - 175 = 300 - 175 = 125
910 - 268 - 232 = 910 - (268 + 232) = 910 - 500 = 410
517 - 117 - 58 - 142 = (517 - 117) - (58 + 142) = 400 - 200 = 200
647 - 85 + 53 - 15 = (647 + 53) - (85 + 15) = 700 - 100 = 600

3.

猩猩的身高是多少厘米?

3. 430 - 205 - 95 = 130(cm)