The four operations
Adding and subtracting mentally Let’s Learn Together 1 We can use our knowledge of counting in 100s to add 99. What is 367 + 99?
I know that 367 + 100 = 467.
+100
−1
367
467
350 500 420 430 440 450 460 470 480 490 360 370 380 390 400 410
466
+99
Adding on 100 is one too many. We can take away 1 to find the answer: 367 + 99 = 466. 2 We can use a number line to find the difference between two numbers. How could we find the difference between 789 and 1002?
789 to 790 is 1 .
1000 to 1002 is 2 .
+2
+10
+1
790 to 800 is 10 .
1000 1002
800
789 790
800 to 1000 is 200 .
+200
Let’s Practise
What is the difference between: (a) 3998 and 5000 (b) 995 and 1032 (c) 18001 and 19003?
1
There are different ways that you can use the number line. Did you do it the same way?
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01/12/2021 15:03
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