The third graders are working on mastering their 5s and 10s facts.
10s are easy! You just stick a zero after the number you’re multiplying. 3 x 10 = 30
When multiplying by 5, multiply the number by 10 and take half of it. 3 x 5 = 1/2 of 3 x 10 = 15
Odds always end in a five, evens always end in a zero.
Practice at home with a deck of cards. Leave a 10 or 5 out face up. Then turn the deck over and multiply the 10 (or 5) by the next card you flip as fast as you can! See how many you can get in 1 minute 🙂