Numeracy
Numeracy
Mental strategies for addition and subtraction with Mrs Evans.mp4
Mental calculations with Mrs Evans
Today you are going to apply your knowledge of place value to add and subtract 3 and 4 digit numbers.
Sometimes you can use different methods depending on the numbers you have. Remember you may not always have to use column addition, you can sometimes use mental strategies too.
Today you will be solving ‘hardly any work’ additions and subtractions! These are super easy as it usually only involves changing a couple of digits or doing a little counting back or counting on in your heads.
Look at this calculation
4020 + 304
4020 + 304 = 4324. What did you do? Why was it so easy? All we had to do was add each place value, so all that changed in the first numbers was the 0 in the hundreds changed to 3 hundreds and the 0 in the ones changed to 4! The thousands and the tens stayed the same.
Look at this sum
5286 + 1500 = Which digits involved no work and which involved a little bit of work?
Remember if you do need to use column addition how you lay out your column addition is important using the correct column for each digit- always starting with the units!
I have allocated some videos to reinforce addition and subtraction on your bug club accounts.