Answer:

method of mental computation?

1.The "9-trick". To add 9 to any number, first add 10, and then subtract 1.

2.Doubles + 1.

3.Use addition facts when adding bigger numbers.

4.Subtract by adding.

5.Five times a number.

6.Four and eight times a number.

7.Multiply in parts.

method of property of multiplication over addition?

you can use distributive property of multiplication

method of using diagonal columns?

Finding squares I'm not sure

correct me if I am wrong

Pa brainliest po