Final answer:
Amy can use the same mathematical facts to find the new total number of counters after adding one more row of 9, as mathematical rules such as addition and multiplication are consistent and universally applicable.
Step-by-step explanation:
When Amy adds one more row of 9 counters to her array, she can still use the previously established mathematical facts to find the total number of counters. This is because mathematical operations such as addition and multiplication are consistent and apply universally, regardless of the context or changes in quantity, as long as they are done correctly. If Amy had a total that was calculated by multiplying the number of rows by the number of counters in each row, she can simply add 9 (the number of counters in the new row) to the previous total to find the new total number of counters. Alternatively, she can multiply the new number of rows by the number of counters in each row if multiplication was the operation used previously. This demonstrates the commutative property of addition, which allows for reordering in simple addition. Also, if multiplication was used initially, we can see the application of the distributive property, as multiplying the number of rows by the number of counters per row can include this additional row without altering the initial setup.