Lesson 15 Riddles

    • Let’s use what we know about adding and subtracting to solve and write riddles about people’s ages.

Warm-up Notice and Wonder: Birthday Candles

What do you notice? What do you wonder?

Girl blowing out candles on a cake. 
Boy blowing out candles on cake.

Activity 1 Kiran’s Age Riddles

Solve Kiran’s age riddles. Show your thinking. Use a number line if it helps.

  1. I’m 7. My sister is 5 years older than I am. How old is she?

    years old

  2. If you add 27 years to my sister’s age, you get my mom’s age. How old is my mom?

    years old

  3. My brother is 24 years younger than my mom. How old is my brother?

    years old

  4. My grandma is 53 years older than my brother. How old is my grandma?

    years old

  5. My uncle is 21 years younger than my grandma. How old is my uncle?

    years old

  6. My uncle is 33 years older than my cousin. How old is my cousin?

    years old

  7. There is a 50 year difference between my grandpa’s age and my cousin’s age. How old is my grandpa?

    years old

Activity 2 Write Riddles

  1. Complete the table by writing down 4 people you know with different ages.

    person’s first name

    age (years)

  2. Come up with 3 mathematical questions to ask your partner.

    Question 1:

    Question 2:

    Question 3:

  3. Solve your partner’s riddles. Show your thinking using a number line or equation.