Of course! Let's solve each proportion problem step by step. The goal is to find the missing number (represented by a box `□`) that makes the two fractions equal — that is, they form a true proportion.
We'll use the
cross-multiplication method: For any proportion `a/b = c/d`, we know that `a × d = b × c`.
---
Problem 1:
`2/5 = 6/□`
Cross-multiply:
`2 × □ = 5 × 6`
`2 × □ = 30`
Divide both sides by 2:
`□ = 15`
✔ Answer:
15
---
Problem 2:
`4/□ = 8/10`
Cross-multiply:
`4 × 10 = □ × 8`
`40 = 8 × □`
Divide both sides by 8:
`□ = 5`
✔ Answer:
5
---
Problem 3:
`3/4 = 15/□`
Cross-multiply:
`3 × □ = 4 × 15`
`3 × □ = 60`
Divide both sides by 3:
`□ = 20`
✔ Answer:
20
---
Problem 4:
`7/□ = 21/24`
Cross-multiply:
`7 × 24 = □ × 21`
`168 = 21 × □`
Divide both sides by 21:
`□ = 8`
✔ Answer:
8
---
Problem 5:
`8/□ = 2/3`
Cross-multiply:
`8 × 3 = □ × 2`
`24 = 2 × □`
Divide both sides by 2:
`□ = 12`
✔ Answer:
12
---
Problem 6:
`15/20 = 3/□`
Cross-multiply:
`15 × □ = 20 × 3`
`15 × □ = 60`
Divide both sides by 15:
`□ = 4`
✔ Answer:
4
---
Problem 7:
`15/□ = 3/8`
Cross-multiply:
`15 × 8 = □ × 3`
`120 = 3 × □`
Divide both sides by 3:
`□ = 40`
✔ Answer:
40
---
Problem 8:
`12/16 = 3/□`
Cross-multiply:
`12 × □ = 16 × 3`
`12 × □ = 48`
Divide both sides by 12:
`□ = 4`
✔ Answer:
4
---
Problem 9:
`3/6 = □/2`
Cross-multiply:
`3 × 2 = 6 × □`
`6 = 6 × □`
Divide both sides by 6:
`□ = 1`
✔ Answer:
1
---
Problem 10:
`□/5 = 16/20`
Cross-multiply:
`□ × 20 = 5 × 16`
`20 × □ = 80`
Divide both sides by 20:
`□ = 4`
✔ Answer:
4
---
Problem 11:
`□/4 = 4/16`
Cross-multiply:
`□ × 16 = 4 × 4`
`16 × □ = 16`
Divide both sides by 16:
`□ = 1`
✔ Answer:
1
---
Problem 12:
`4/8 = □/2`
Cross-multiply:
`4 × 2 = 8 × □`
`8 = 8 × □`
Divide both sides by 8:
`□ = 1`
✔ Answer:
1
---
##
✔ Final Answers (in order):
1.
15
2.
5
3.
20
4.
8
5.
12
6.
4
7.
40
8.
4
9.
1
10.
4
11.
1
12.
1
You can now fill in all the boxes on your worksheet with these numbers!
Let me know if you’d like to see how to simplify fractions or check your answers another way! 😊
Parent Tip: Review the logic above to help your child master the concept of portion worksheet.
