To verify the quantity of notebooks in the most straightforward way, Mrs. Mariela can follow these steps:
1. **Grouping by Thousands:** Since Mrs. Mariela has 3,570,140 notebooks, she can group them by thousands. This means she has 3 groups of 1,000,000 notebooks, 5 groups of 100,000 notebooks, 7 groups of 10,000 notebooks, and 0 single notebooks.
2. **Using Place Value:** Mrs. Mariela can use the place value system to read the quantity of notebooks. Starting from the left, the first digit represents millions, the second digit represents hundreds of thousands, the third digit represents tens of thousands, and so on. By reading the number in this way, she can easily determine the total quantity.
3. **Counting in Sets:** Another method is for Mrs. Mariela to count the notebooks in sets or batches. For example, if she counts and bundles notebooks in sets of 100 or 1000, it can help her keep track of the total quantity more efficiently.
By employing these methods, Mrs. Mariela can accurately verify the quantity of notebooks she has for sale without much complexity.