Math Activities #10: Larger number subtraction with regrouping

100’s chart

grille-de-nombres-1-a-1000 (dragged)

grille-de-nombres-1-a-1000 (dragged) 2

  1. Please start by watching this informational video. You might have to watch it twice or three times. Subtraction with Regrouping – Math Video for 2nd Grade
  2. Once you have watched the video, try the worksheet. 

sous_nombre_2_diminuende_99_12_001-dragged

Use a calculator to mark your work. Use a pen to make corrections so that you can see where you made your mistakes. What do you notice about the mistakes you made?

https://www.online-calculator.com

  1. Word question:

1 dollar

2 dollar

5cents

10 cents

25 cents

Option A: 6,75$

On non! Sylvie a cassé sa tirelire/piggy bank. Toute sa monnaie est tombée! Elle avait 6 dollars et 75 sous. Dessine 6,75$ avec le moins de pièces possible. Dessine 6,75$ avec le plus de pièces possible.

Oh no!  Sylvie broke her piggy bank. All her money fell to the ground. She had $6.75. Can you represent $6.75 with the least amount of coins  possible. Can you represent $6.75 with the most amount of coins and bills possible.  You can draw your answer. You can also  cut and paste the coins from the play money below to help you organise your work.

675 (2)

Option B: 0,65$

On non! Sylvie a cassé sa tirelire/piggy bank. Toute sa monnaie est tombée! Elle avait 0,65 sous. Dessine 0,65¢  avec le moins de pièces possible. Dessine 0,65¢ avec le plus de pièces possible.

Oh no!  Sylvie broke her piggy bank. All her money fell to the ground. She had 0,65¢. Can you represent 0,65¢ with the least amount of coins possible. Can you tepresent 0,65¢ with the most amount of coins possible.  You can draw your answer. You can also  cut and paste the coins from the play money  below to help you organise your work

065¢

  1. There is another strategy for subtracting with regrouping called Make it Round. The idea is that if you are subtracting only 10’s and no 1’s, your equation will be easier to solve (for example 43-20 is easier to solve than 41-18). In this case, you add the same number to both your minuend and subtrahend (the number you are subtracting from and the number you are subtracting) so that your subtrahend is “round” (10/20/30/40 etc). Here is an example:

35-19 

(35+1)-(19+1)

36-20= 16

Practice: Can you make the following equations round?

28 + __ = 30

46 + __ = 50

59 + __ = 60

46 + __ = 50

Activity: Try using this strategy to solve the following questions. Remember- how much do you need to add to each number to make the subtrahend “round” (a multiple of 10). Parents I have attached the answer key at the bottom.

45 – 19 =

56 – 18 =

33 – 17 =

47 – 28 =

61 – 49 =

75 – 28 =

Game: The Biggest Difference