Mateo is gathering workout clothes. There are 3 pairs of running shoes and 7 workout shirts to choose from. For the pair of workout shorts, Mateo has 2 options. How many different workout outfits can Mateo make? square workout outfits

## Step 1: Calculate the combinations of shoes and shirts<br />### Mateo has 3 choices for shoes and 7 choices for shirts. The number of combinations of shoes and shirts is found by multiplying the number of choices for each: $3 \times 7 = 21$.<br />## Step 2: Calculate the total outfit combinations<br />### Mateo has 21 combinations of shoes and shirts, and 2 choices for shorts. The total number of different workout outfits is found by multiplying the combinations of shoes and shirts by the number of choices for shorts: $21 \times 2 = 42$.