Fill in the appropriate operation symbol in o! 4o4o4o4 = 1 this 4o4o4o4 is the same, but the number is different We need 4o4o4o4 to get the number of 2 1 7 8. Thank you

Fill in the appropriate operation symbol in o! 4o4o4o4 = 1 this 4o4o4o4 is the same, but the number is different We need 4o4o4o4 to get the number of 2 1 7 8. Thank you

4÷4+4-4=1
4÷4+4÷4=2
4+4-4÷4=7
4+4+4-4=8

Fill in the appropriate letter or number in () according to the law of operation
ac＋bc＝（ ＋ ）．（ ）
3x＋5x＝（ ＋ ）．（ ）
a＋（b＋x）＝（ ＋ ）＋（ ）
4．（x＋3）＝（ ）．（ ）＋（ ）．（ ）

ac＋bc＝（ a＋b ）．（ c ）
3x＋5x＝（ 3＋5 ）．（ x ）
a＋（b＋x）＝（ a＋ b）＋（ x ）
4．（x＋3）＝（4 ）．（ x）＋（4 ）．（ 3）

Using the operation law, fill in the appropriate number in (). () × 34 + () × 66 = 28 × (+)
Using the law of operation, fill in the appropriate number in ()
（ ）×34+（ ）×66=28×( + )

This is the problem of multiplicative allocation rate
a ×b+a*c=a ×（b+c）
28 ×34+28 ×66=28 ×（34+66）

According to the operation law we have learned, fill in the appropriate number (1.5 * 1.2) *] = 1.2 in the following []*（
According to the operation law we have learned, fill in the appropriate number (1.5 * 1.2) *] = 1.2 * (] * 6) in the following []

﹙1.5×1.2﹚×2=1.2×﹙1.5×2﹚