Example of power of 10:
Any exponent with base 10 is an example.
We can write 1000, that is 10^3, so it is an example of a power of 10.
If we write 8, that is 2^3, this a non-example of power of 10.
Multiple of 10^2:
A multiple of 10^2 is any number that, when divided by 100 or 10^2, gives a remainder of 0.
For example, 300 is a multiple of 10^2, beacuse when divided by 100 gives an integer (300/100=3).
The number 234 is a non-example of a multiple of 10^2, as it gives a remainder of 34 when divided by 100.
Expression with a variable:
For example, 3x is a expression with a variable, that is x.
If we just write 3, this is a constant and there is no variable, so this is a non-example.
Underestimate of 532 * 11:
When multiplying mentally we can simplify the numbers in order to approximate the calculation. When we round down one or more of the factors, we will underestimate the product.
In this case, if we approximate this product as 500*10=5000, we have an underestimated approximation.
If we round up, we are overestimating: for example 550*11=5500+550=6050 is a non-example of underestimation (it is in fact, overestimating the result).