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Elementary math lessons to learn
'Subtract 99 from multiple of 10' for 5th grade
5th grade / Add + Subtract / Subtract 89, 99, 109 / Subtract 99 from multiple of 10
Subtract 99 from multiple of 10
When you subtract from a large number, you can sometimes use simple tricks to help you. This is especially so when the number to be subtracted has a unit value of 1 or 9.
When subtracting 99, it is often easier to first subtrat 100, and then subtract 1 more to get the answer.
130 - 99 = (130 - 100) + 1 = 30 + 1
Of course, this trick also works when the initial number is not a multiple of 10:
137 - 99 = (137 - 100) + 1 = 37 + 1
You can use a similar technique whenever the number to be subtracted has a unit value of 9 (or 1 in which case you subtract 1 rather than add as the second step).
With these interactive math lessons you will be learning "Subtract 99 from multiple of 10" from
5th grade / Add + Subtract in 3 easy steps. The math in our lessons consists of 8 questions that ask you to subtract 99 from a number by first subtracting 100 and then adding 1 to the result.
There are 3 easy math lesson activities in this "Subtract 99 from multiple of 10" tutorial. These activities progress step by step to help you the learner gradually master this math topic. The activities are based on "3 stage questioning", a method of learning that quickly and easily builds your confidence as you work through the short series of lessons that strengthen your knowledge of the math that you want to learn.
When you have completed the tutorial for a topic, you should try some of our games before finally doing the test for your chosen topic. See the Help box below for detailed instructions on how to use the lesson activities to help you learn your math more easily.
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'Subtract 99 from multiple of 10' for 5th grade
Introduction to the math topic
You start the tutorial with a lesson that introduces the math you will be learning. You will see a set of questions one at a time, and for each question you will see the written answer and also hear the answer to that question.
Repeat the question/answer by clicking on the brown speaker sign. Repeat the question/answer and expand the question graphic by clicking on the question box. Move between questions using the arrow buttons below the question. If there is additional information available for your chosen topic, the "i" button on the left upright bar will be brown on white. Click on the button to load the additional lesson information into the main interface.
Either / Or math lesson
This lesson moves on from the "Introduction" lesson and offers you two possible answers to each question. So, you will see a question then a voice will ask "Is this ... or is it ..." and you will have to choose which of the answers is the one that matches the question.
You choose an answer by clicking or tapping on one of the two answer boxes below the question. You can play the audio for each answer again by clicking on the speaker icon beside the written answer (if robot speech is available and enabled). The program will let you know each time whether you answered correctly. A star will light up red for a wrong answer or white/black for a correct answer.
This lesson asks you the questions in a random order compared to the introduction. At the end of the lesson, you can choose whether to repeat the lesson or move on to the next one.
What is it? math lesson
The final lesson of the tutorial shows you multiple possible answers for each question - you must choose the correct one. You are asked a question and below it are a list of two, three, or four possible written/numeric answers from this topic. Pressing the speaker icon will play the math audio for that answer.
For each picture, click on the answer that matches the question. The program will tell you whether you are right or not. As with the Either / Or activity a system of stars indicate your right and wrong answers. The What is it? lesson will show you all the questions you learned in the Introduction but in a random order.
When you complete the "What is it?" lesson, you can choose whether to go on to play some games with this topic, or whether you want to repeat some or all of the lesson activities in this tutorial. You should expect to get 80% of the answers correct in most of the activities before trying some of the Math games with this topic.
