🏭
Grade 4 Math · World 3: Multiplication Mill · Level 29
Two Digits Times Two Digits
Split 39 × 15 into four parts on an area model.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 29
- A store gets 39 cases of popcorn with 15 bags in each case. How many bags? Split both numbers: 39 is 30 and 9, and 15 is 10 and 5.
- Now there are four parts: 30 times 10 is 300, 30 times 5 is 150, 9 times 10 is 90, and 9 times 5 is 45.
- Add the four parts: 300 plus 150 is 450, plus 90 is 540, plus 45 is 585. That's 585 bags of popcorn!
Georgia's K-12 Mathematics Standards:
- 4.NR.2.3 — Solve relevant problems involving multiplication of a number with up to four digits by a 1-digit whole number or involving multiplication of two two-digit numbers using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.