This is a maths strategy that requires all of your times tables to be known. For example, 4 x 243. Place value is also needed so you split 243 into 200+40+3. Then you make 4 groups of 200+40+3 because you are multiplying by that number. 4 x 3= 12, so you cross out the 3 in your groups. 4 x 40 is 160, so cross out all the 40s. 4 x 200 is 800, so cross out the 200s. Add 12+160+800 together, and you get 972. 4 x 243= 972.
Hello Phyu sin, great maths skills! This seems like a great maths strategy to use when multiplying with large numbers. I like how you explained the maths strategy very well. Keep up the great work!
Selina